TemplateBinding not working with command WPF

TemplateBinding not working with command WPF - c#

I'm currently working on a new combobox that has a button called 'Add' that needs to be fire a command when it clicked, Basically it will start a new window to add new row in the database.
I have created a new control that inherits from Combobox and added a new command called 'AddCommand' and then created a Template that will add the new button to the combobox which is called 'Add'. When I bind the command of the button to the 'AddCommand' through TemplateBinding it won't work.
I have created a custom control as follows:
public class ZeroOneCombobox : ComboBox
{
public ICommand AddCommand
{
get
{
return (ICommand)GetValue(AddCommandProperty);
}
set
{
SetValue(AddCommandProperty, value);
}
}
public static readonly DependencyProperty AddCommandProperty =
DependencyProperty.Register("AddCommand", typeof(ICommand), typeof(ZeroOneCombobox));
}
Then I have created a Control Templete As Follows:
<ControlTemplate x:Key="ZeroOneComboBoxControl" TargetType="{x:Type zoc:ZeroOneCombobox}"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero2">
<Grid x:Name="templateRoot" SnapsToDevicePixels="True">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup Grid.Column="2" x:Name="PART_Popup" AllowsTransparency="True" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Grid>
<Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<VirtualizingStackPanel Name="ItemPanel" IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Contained" />
</ScrollViewer>
</Border>
</Grid>
</Themes:SystemDropShadowChrome>
</Popup>
<Button x:Name="Add" Grid.Column="0" Content="+" Style="{StaticResource ComboboxButton}" Command="{TemplateBinding AddCommand}" />
<ToggleButton x:Name="toggleButton"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}"
Grid.ColumnSpan="2"
Grid.Column="2"
IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="Focusable" Value="False"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" BorderBrush="#FFACACAC" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="True">
<Border.Background>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="True" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="Arrow" Data="F1M0,0L2.667,2.66665 5.3334,0 5.3334,-1.78168 2.6667,0.88501 0,-1.78168 0,0z" Fill="#FF606060" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFABADB3"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF569DE5"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFBFBFBF"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="#FFF0F0F0"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFD9D9D9"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFBFBFBF"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<TextBox x:Name="contentPresenter" Grid.Column="2"
Text="{TemplateBinding Text}"
HorizontalAlignment="Stretch"
IsHitTestVisible="False" Margin="{TemplateBinding Padding}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
VerticalAlignment="Stretch"
BorderThickness="0"
IsEnabled="True"
IsReadOnly="False"
IsTabStop="False" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="True">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="False">
<Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="True"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="False"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="False"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
When I bind a command to the ViewModel like follow:
<zoc:ZeroOneCombobox x:Name="Comb" DisplayMemberPath="Name" Template="{StaticResource AdvComboBoxControl}"
AddCommand="{Binding ViewAccountCommand}" Margin="163,234,308.6,154" />
The Command won't fire when I click on the add button...
Please help!

Related

WPF ComboBox background of selected item text box

I am locking for to change the background and foreground of the textbox shows the selected item in a combobox. I changed the background of the items but I can not change the textbox.
enter image description here
I have the follow code in App.xaml:
<Style x:Key="CmbStyleItem1" TargetType="{x:Type ComboBoxItem}">
<Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Background}"/>
</Style>
<Style x:Key="myComboBoxStyle" TargetType="ComboBox">
<Setter Property="Margin" Value="0"/>
<Setter Property="SnapsToDevicePixels" Value="True"/>
<Setter Property="Padding" Value="4,1"/>
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="VerticalAlignment" Value="Stretch"/>
<Setter Property="Foreground" Value="{Binding ComboForeColor}"/>
<Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="FontSize" Value="26"/>
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="ItemContainerStyle" Value="{DynamicResource CmbStyleItem1}"/>
</Style>
And this is the code I have MainWindow.xalm
<ComboBox x:Name="cbGroups" Background="{StaticResource ComboBox.Static.Background}" Style="{StaticResource myComboBoxStyle2}" Width="269" Height="60" DisplayMemberPath="Name" SelectedValue="{Binding Groups_DB.Records}" SelectionChanged="cbGroups_SelectionChanged" Margin="10,10,10,10">
</ComboBox>
can Someone help me?

<Window.Resources>
<Style x:Key="FocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle Margin="2" StrokeDashArray="1 2" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" SnapsToDevicePixels="true" StrokeThickness="1"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<SolidColorBrush x:Key="TextBox.Static.Background" Color="#FFFFFFFF"/>
<Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="AllowDrop" Value="true"/>
<Setter Property="MinWidth" Value="0"/>
<Setter Property="MinHeight" Value="0"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<SolidColorBrush x:Key="ComboBox.Static.Background" Color="pink"/>
<SolidColorBrush x:Key="ComboBox.Static.Border" Color="#FFACACAC"/>
<SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="#FF606060"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="green"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="#FFABADB3"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="#FF000000"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="#FF7EB4EA"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="#FF7EB4EA"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="#FF000000"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="#FF569DE5"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="#FFF0F0F0"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="#FFD9D9D9"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/>
<Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Focusable" Value="false"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" Background="{StaticResource ComboBox.Static.Background}" BorderBrush="{StaticResource ComboBox.Static.Border}" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="true">
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="arrow" Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Border}"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Placement="Bottom" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}">
<theme:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MinWidth="{Binding ActualWidth, ElementName=templateRoot}" MaxHeight="{TemplateBinding MaxDropDownHeight}">
<Border x:Name="dropDownBorder" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</theme:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<Border x:Name="border" Background="{StaticResource TextBox.Static.Background}" Margin="{TemplateBinding BorderThickness}">
<TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Opacity" TargetName="border" Value="0.56"/>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="true">
<Setter Property="Foreground" Value="Black"/>
</Trigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<ControlTemplate x:Key="ComboBoxTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" Placement="Bottom" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}">
<theme:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MinWidth="{Binding ActualWidth, ElementName=templateRoot}" MaxHeight="{TemplateBinding MaxDropDownHeight}">
<Border x:Name="dropDownBorder" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</theme:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<ContentPresenter x:Name="contentPresenter" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" Content="{TemplateBinding SelectionBoxItem}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">
<Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
<Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Border}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="Padding" Value="6,3,5,3"/>
<Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
<Setter Property="ScrollViewer.PanningMode" Value="Both"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template" Value="{StaticResource ComboBoxTemplate}"/>
<Style.Triggers>
<Trigger Property="IsEditable" Value="true">
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Padding" Value="2"/>
<Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<ComboBox Style="{DynamicResource ComboBoxStyle1}" x:Name="cbGroups" Width="269" Height="60" ItemsSource="{Binding }"
DisplayMemberPath="Name" SelectedValuePath="Name" SelectedValue="{Binding Path=Name}">
</ComboBox>
</Grid>
codebehind:
public partial class MainWindow : Window
{
public ObservableCollection<Item> Itmes { get; set; } = new ObservableCollection<Item>()
{
new Item() { Name="name1" },
new Item() { Name="name2" },
new Item() { Name="name3" },
new Item() { Name="name4" },
};
public MainWindow()
{
InitializeComponent();
cbGroups.ItemsSource = Itmes;
DataContext=this;
}
}
public class Item
{
public string Name { get; set; }
}
The result:

WPF combobox prevent selection update

I want to be able to select a value in a ComboBox but avoid the selected value updating.
In other words, for the picture above, I want the empty selection to remain empty when one of the items is selected.
I've tried a ton of different solutions - various bindings on SelectedIndex, SelectedValue, SelectionChanged, playing with IsEditable, IsReadonly, IsHitTestVisible, Text, etc, etc, etc.
How can I prevent the combobox from automatically updating the text on selection, but still have it able to select a choice?
Sample code:
<ComboBox
IsReadOnly="True"
IsEditable="False"
Text="..."
>
<ComboBoxItem>
<TextBlock>Close</TextBlock>
</ComboBoxItem>
<ComboBoxItem>
<TextBlock>Delete</TextBlock>
</ComboBoxItem>
</ComboBox>

As an experienced WPF developer, I'll put some light on this problem.
Basically, you have tried a ton of different solutions using the wrong instruments.
In WPF each control has a default style, which fully describes what you'll see on the screen (nothing hidden here). What is not that obvious, however, is how to take a look at the default style of a control.
(I work with VS 2013, but the steps described below should work in later versions as well)
Create a new project in 'Blend for Visual Studio 2013"
In the "Assets" tab search box type "ComboBox" and double click on it
Right click on the ComboBox you've just added in the "Objects and timeline" panel and select "Edit template -> Edit a copy..."
Switch to code view (the button is on the top right side)
Yeah, the default styles are quite lengthy!
Now, what we are interested in is the ControlTemplate. There must be some control in this tempplate responsible for displaying the selected item. If you are in a hurry, just find it and delete the appropriate binding.
Below is an example solution, which I would call "Couple hours before deadline solution". Read the comments in the XAML for the proper approach.
<Window x:Class="ComboBoxAdventures.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero2"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style x:Key="FocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<LinearGradientBrush x:Key="ComboBox.Static.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0.0"/>
<GradientStop Color="#FFE5E5E5" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Static.Border" Color="#FFACACAC"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="#FFABADB3"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="#FF000000"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="#FF7EB4EA"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="#FF7EB4EA"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="#FF000000"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="#FF569DE5"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="#FFF0F0F0"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="#FFD9D9D9"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="#FF606060"/>
<Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Focusable" Value="false"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" BorderBrush="{StaticResource ComboBox.Static.Border}" BorderThickness="{TemplateBinding BorderThickness}" Background="{StaticResource ComboBox.Static.Background}" SnapsToDevicePixels="true">
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="arrow" Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Border}"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="ComboBoxTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<!-- This content presenter displays the selected item.
The easiest way is just to remove the Content binding as shown below.
The proper way to do those kind of things, however, is to inherit from ComboBox,
define a dependency property ShowSelectedItem and then add a trigger for the ContentPreseneter below,
which changes the Content based on the value of the ShowSelectedItem.
You'll also need a custom IValueConverter for mapping bool to Hidden/Visible and some
googling about Generic.xaml and how to overwrite the DefaultStyle dependency property in the static constructor.
You may also wonder why I didn't just comment out the whole ContentPresenter.
Well, lets say it just keeps the 'backbone' of the control :)
-->
<ContentPresenter x:Name="contentPresenter" Tag="I have removed only this part: Content='{TemplateBinding SelectionBoxItem}'"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
Content="" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
IsHitTestVisible="false" Margin="{TemplateBinding Padding}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
</ContentPresenter>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<SolidColorBrush x:Key="TextBox.Static.Background" Color="#FFFFFFFF"/>
<Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="AllowDrop" Value="true"/>
<Setter Property="MinWidth" Value="0"/>
<Setter Property="MinHeight" Value="0"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<Border x:Name="border" Background="{StaticResource TextBox.Static.Background}" Margin="{TemplateBinding BorderThickness}">
<TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Opacity" TargetName="border" Value="0.56"/>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="true">
<Setter Property="Foreground" Value="Black"/>
</Trigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="Style.ComboBox.Ghost" TargetType="{x:Type ComboBox}">
<Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
<Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Border}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="Padding" Value="6,3,5,3"/>
<Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
<Setter Property="ScrollViewer.PanningMode" Value="Both"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template" Value="{StaticResource ComboBoxTemplate}"/>
<Style.Triggers>
<Trigger Property="IsEditable" Value="true">
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Padding" Value="2"/>
<Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<ComboBox Style="{StaticResource Style.ComboBox.Ghost}" ItemsSource="{Binding SelectedDummyModel}" SelectedItem="{Binding DummyModels}"/>
</StackPanel>
</Window>

Here's something I came up with based on adding buttons to the combobox.
This is just two buttons added to the combobox.
<ComboBox x:Name="cboBox" HorizontalAlignment="Left" VerticalAlignment="Top" Width="151" Margin="182,132,0,0" SelectionChanged="cboBox_SelectionChanged" Grid.Column="1" Height="22">
<Button Content="Close" Width="141" Click="Button_Close" Height="51"/>
<Button Content="Delete" Width="141" Click="Button_Delete" Height="51"/>
</ComboBox>
I then went into the code behind and added code to handle the click event for each button.
As you will see we aren't even dealing with the combobox other than using it to show the buttons and then closing the dropdown upon clicking one of the buttons.
private void Button_Close(object sender, RoutedEventArgs e)
{
lbl1.Content = "Close Clicked";
cboBox.IsDropDownOpen = false;
}
private void Button_Delete(object sender, RoutedEventArgs e)
{
lbl1.Content = "Delete Clicked";
cboBox.IsDropDownOpen = false;
}
I really need to get better versed with WPF. I actually enjoyed messing with this.

set combo box selected item value to null through data trigger

I am trying to set Combobox Selected Item property to null through Control Template I've added Checkbox so I can use datatrigger and set SelectedItem to null when Checkbox isChecked is true. Basically Im trying to add clear filter checkbox that will show up when SelectedItem has some value, and upon clicking this checkbox selected item will null itself
PS.Initially I was going to use button instead of checkbox but Im not sure how to wire it up all inside Dictionary
<CheckBox Panel.ZIndex="2" Width="20" HorizontalAlignment="Left" Foreground="Red" FontWeight="Bold" Background="Red" Content="X" x:Name="chkBOX">
<CheckBox.Style>
<Style TargetType="CheckBox">
<Style.Setters>
<Setter Property="Visibility" Value="Visible"/>
<Setter Property="IsEnabled" Value="True"/>
<Setter Property="VerticalAlignment" Value="Center"/>
</Style.Setters>
<Style.Triggers>
<!-- If selected item is null hide toggle button -->
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>
And now Im looking to interact with it so selected item goes null when checkbox is checked
Hope thats ok :)
EDIT:
I've made SOME progress
I can null selected item with below
however this only works if Selected item is not binded on my window form IE
this works
<ComboBox Grid.Row="1" Margin="10,0,0,0" ItemsSource="{Binding Users}" Tag="Select Full Name"
DisplayMemberPath="FullName" Template="{DynamicResource ComboBoxWithPlaceholder}" />
this doesnt work
<ComboBox Grid.Row="1" Margin="10,0,0,0" ItemsSource="{Binding Users}" Tag="Select Full Name"
DisplayMemberPath="FullName" SelectedItem="{Binding SelectedUserFullName}" Template="{DynamicResource ComboBoxWithPlaceholder}" />

Nullable combobox with placeholeder
Link to gif
<ControlTemplate x:Key="ComboBoxWithPlaceholder" x:Name="cb" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="True">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="16"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<ToggleButton Panel.ZIndex="2" Width="16" HorizontalAlignment="Left" Foreground="Red" ToolTip="Clear Selection" Opacity="0.5"
FontWeight="Bold" Background="Transparent" BorderThickness="0" Content="X" x:Name="toggleB">
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Style.Setters>
<Setter Property="VerticalAlignment" Value="Center"/>
</Style.Setters>
<Style.Triggers>
<!-- If selected item is null hide toggle button -->
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"/>
<!-- When hidden ensure its not checked -->
<Setter Property="IsChecked" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ToggleButton.Style>
</ToggleButton>
<!-- Placeholder textblock text is bound to tag property of combobox -->
<TextBlock Grid.ColumnSpan="2" Grid.Column="0" x:Name="tb" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Foreground="DimGray"
IsHitTestVisible="False" Panel.ZIndex="1" Text="{Binding Tag,RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}}">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Setters>
<Setter Property="Visibility" Value="Hidden"/>
<Setter Property="Margin" Value="5,0"/>
<Setter Property="VerticalAlignment" Value="{Binding VerticalContentAlignment,RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}}"/>
</Style.Setters>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
<Popup x:Name="PART_Popup" AllowsTransparency="True" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" VerticalContentAlignment="Center"
Background="{TemplateBinding Background}" Grid.Column="0" Grid.ColumnSpan="3" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="Focusable" Value="False"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" BorderBrush="#FFACACAC" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="True">
<Border.Background>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="True" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="Arrow" Data="F1M0,0L2.667,2.66665 5.3334,0 5.3334,-1.78168 2.6667,0.88501 0,-1.78168 0,0z" Fill="#FF606060" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFABADB3"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF569DE5"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFBFBFBF"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="#FFF0F0F0"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFD9D9D9"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFBFBFBF"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<ContentPresenter Grid.Column="1" x:Name="contentPresenter" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
IsHitTestVisible="False" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
</ContentPresenter>
</Grid>
<ControlTemplate.Triggers>
<!-- If selected set selected item to null-->
<DataTrigger Binding="{Binding IsPressed, ElementName=toggleB}" Value="True">
<Setter Property="SelectedValue" Value="{x:Null}"/>
<Setter Property="SelectedValuePath" Value="{x:Null}"/>
<Setter Property="SelectedItem" Value="{x:Null}"/>
</DataTrigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="True">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="False">
<Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="True"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="False"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="False"/>
</MultiTrigger>
<Trigger Property="CanContentScroll" SourceName="DropDownScrollViewer" Value="False">
<Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
bit I was missing is to set SelectedValuePath and SelectedValue to null as well as Selected item
<DataTrigger Binding="{Binding IsPressed, ElementName=toggleB}" Value="True">
<Setter Property="SelectedValue" Value="{x:Null}"/>
<Setter Property="SelectedValuePath" Value="{x:Null}"/>
<Setter Property="SelectedItem" Value="{x:Null}"/>
</DataTrigger>

changing border of combo box in wpf c#

I want to change combo box border color if it is empty.
I tried with following code, which does not work. For text box, it was working fine.
in xaml
<ComboBox HorizontalAlignment="Left" Height="23" Margin="125,14,0,0" VerticalAlignment="Top" Width="151" Name="CountryName" ItemsSource="{Binding DpData}" DisplayMemberPath="CountryName" SelectedValuePath="CountryID" Grid.Column="1" Grid.ColumnSpan="2" BorderThickness="3" BorderBrush="{x:Null}" />
in C#
if (CountryName.Text == "")
{
CountryName.BorderBrush = Brushes.Red;
}

While Snooping i have found that, BorderBrush property not being set to InnerProperty. Here i've included VisualStudio generated ComboBox template with Modified codes.
<Window.Resources>
<Style x:Key="FocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<LinearGradientBrush x:Key="ComboBox.Static.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0.0"/>
<GradientStop Color="#FFE5E5E5" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Static.Border" Color="#FFACACAC"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="#FFABADB3"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="#FF000000"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="#FF7EB4EA"/>
<LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0.0"/>
<GradientStop Color="#FFDCECFC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="#FF7EB4EA"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="#FF000000"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="#FF569DE5"/>
<LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0.0"/>
<GradientStop Color="#FFC4E0FC" Offset="1.0"/>
</LinearGradientBrush>
<SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="#FF569DE5"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="#FFF0F0F0"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="#FFD9D9D9"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="#FFBFBFBF"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/>
<SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="#FF606060"/>
<Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Focusable" Value="false"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{StaticResource ComboBox.Static.Background}" SnapsToDevicePixels="true">
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="arrow" Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="true">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Border}"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Border}"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Border}"/>
<Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Border}"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="ComboBoxTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<SolidColorBrush x:Key="TextBox.Static.Background" Color="#FFFFFFFF"/>
<Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="AllowDrop" Value="true"/>
<Setter Property="MinWidth" Value="0"/>
<Setter Property="MinHeight" Value="0"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
<Border x:Name="border" Background="{StaticResource TextBox.Static.Background}" Margin="{TemplateBinding BorderThickness}">
<TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Opacity" TargetName="border" Value="0.56"/>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="true">
<Setter Property="Foreground" Value="Black"/>
</Trigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="true"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</MultiTrigger>
<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">
<Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
<Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
<Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Border}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="Padding" Value="6,3,5,3"/>
<Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
<Setter Property="ScrollViewer.PanningMode" Value="Both"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template" Value="{StaticResource ComboBoxTemplate}"/>
<Style.Triggers>
<Trigger Property="IsEditable" Value="true">
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Padding" Value="2"/>
<Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<ComboBox x:Name="Myc" Height="40" BorderThickness="3" BorderBrush="{x:Null}" Style="{DynamicResource ComboBoxStyle1}"/>
Previously Border named templateRoot's BorderBrush property set as
<Border x:Name="templateRoot" BorderBrush="{StaticResource ComboBox.Static.Border}".... />
now that was changed to TemplateBinding.

ComboBox DropDown Trigger isn't working after using ToggleButton

I have a ComboBox Trigger to open the dropdown when the keyboard focus is on it:
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="IsDropDownOpen" Value="True" />
<Setter Property="Foreground" Value="Black" />
</Trigger>
It works fine, however after pressing on the toggle button, the dropdown won't work anymore when keyboard has focus on the combobox. The dropdown will still work by clicking on the toggle button thereafter.
Following is the full control template if it helps to answer my question. Thank you for any input!
<ControlTemplate TargetType="{x:Type ComboBox}">
<Grid x:Name="templateRoot" SnapsToDevicePixels="True">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" AllowsTransparency="True" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
<Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
<Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
<Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>
</Canvas>
<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ScrollViewer>
</Border>
</Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="Focusable" Value="False"/>
<Setter Property="ClickMode" Value="Press"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="templateRoot" BorderBrush="#FFACACAC" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="True">
<Border.Background>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
<Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="True" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
<Path x:Name="Arrow" Data="F1M0,0L2.667,2.66665 5.3334,0 5.3334,-1.78168 2.6667,0.88501 0,-1.78168 0,0z" Fill="#FF606060" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFABADB3"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF569DE5"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFBFBFBF"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="#FFF0F0F0"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFD9D9D9"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFBFBFBF"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border x:Name="Border" Background="White" Margin="{TemplateBinding BorderThickness}">
<TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
<TextBox.Style>
<Style TargetType="{x:Type TextBox}">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="AllowDrop" Value="True"/>
<Setter Property="MinWidth" Value="0"/>
<Setter Property="MinHeight" Value="0"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="False" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TextBox.Style>
</TextBox>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Opacity" TargetName="Border" Value="0.56"/>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="IsDropDownOpen" Value="True" />
<Setter Property="Foreground" Value="Black" />
</Trigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="True">
<Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="shadow" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="False">
<Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsGrouping" Value="True"/>
<Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="False"/>
</MultiTrigger.Conditions>
<Setter Property="ScrollViewer.CanContentScroll" Value="False"/>
</MultiTrigger>
<Trigger Property="CanContentScroll" SourceName="DropDownScrollViewer" Value="False">
<Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
<Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>

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