Tree View Item Selected and Mouse button down event not firing - c#

I have created view models for the tree view. Also created their bindings. I created style trigger so that whenever a tree view item is selected, its background is changed. But the background does not change.I handled the item selected and left mouse down events of tree view item to see if the item is selected or not. But both the events do not fire. Below is the XAML.
<TreeView Grid.Row="0" x:Name="TreeViewLocalSystem" BorderBrush="Transparent" Panel.ZIndex="0">
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="{StaticResource TextBoxBackgroundColor}"></Setter>
</Trigger>
<Trigger Property="IsSelected" Value="False">
<Setter Property="Background" Value="Transparent"></Setter>
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.Resources>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Children}" DataType="{x:Type local:LocalTreeViewItemModel}">
<TreeViewItem Header="{Binding Path=Text}" Selected="TreeViewItem_Selected" HorizontalAlignment="Left" FontSize="{StaticResource MediumFontSize}" MouseLeftButtonDown="TreeViewItem_MouseLeftButtonDown" />
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
What is it that I am doing wrong?
Edit: Another thing that I noticed is that MouseDown event is fired when I do right click but does not fire on left mouse button click.

You could handle the PreviewMouseLeftButtonDown event for the TreeViewItem:
<TreeView Grid.Row="0" x:Name="TreeViewLocalSystem" BorderBrush="Transparent" Panel.ZIndex="0">
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<EventSetter Event="PreviewMouseLeftButtonDown" Handler="TreeViewLocalSystem_PreviewMouseLeftButtonDown" />
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="{StaticResource TextBoxBackgroundColor}"></Setter>
</Trigger>
<Trigger Property="IsSelected" Value="False">
<Setter Property="Background" Value="Transparent"></Setter>
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.Resources>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Children}" DataType="{x:Type local:LocalTreeViewItemModel}">
<TextBlock Text="{Binding Path=Text}" HorizontalAlignment="Left" FontSize="{StaticResource MediumFontSize}" />
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
private void TreeViewLocalSystem_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
//...
}

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Changing Foreground color of ComboBox CheckBox

I am trying to change the foreground color of ComboBoxItem, however it does not apply, what am I doing wrong? Also I'm trying to change the foreground color of hovers on ComboBoxItem which does not work as well.
Here is my xaml:
<ComboBox Foreground="Yellow" Name="txtDispatch" HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Margin="0,0,15,0" Grid.Column="2" Grid.Row="0" materialDesign:HintAssist.Hint="Select Dispatch" SelectionChanged="txtDispatch_SelectionChanged">
<ComboBox.ItemTemplate >
<DataTemplate >
<CheckBox Foreground="Yellow" Name="chkDispatch" Width="220" Checked="txtDispatch_Checked" Unchecked="txtDispatch_Checked" Content="{Binding Dispatch.id}" IsChecked="{Binding Check_Status}" CommandParameter="{Binding Dispatch.id}" />
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<ComboBox Foreground="Black">
<ComboBox.Style>
<Style TargetType="ComboBox">
<Setter Property="ItemContainerStyle">
<Setter.Value>
<Style TargetType="ComboBoxItem">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="False">
<Setter Property="Background" Value="White"/> <!--Optional-->
<Setter Property="Foreground" Value="Red"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="White"/> <!--Optional-->
<Setter Property="Foreground" Value="Yellow"/>
</Trigger>
</Style.Triggers>
</Style>
</Setter.Value>
</Setter>
</Style>
</ComboBox.Style>
<!-- Items List-->
<ComboBoxItem>1</ComboBoxItem>
<ComboBoxItem>2</ComboBoxItem>
<ComboBoxItem>3</ComboBoxItem>
<ComboBoxItem>4</ComboBoxItem>
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Very Simple. Use the style.

How to clear TextBox text property in Binding inside a HierarchicalDataTemplate

I can not clean the text property of a TextBox when the user clicks inside it. The TextBox is inside a HierarchicalDataTemplate but the trigger doesn't work.
My code is as follows:
<HierarchicalDataTemplate x:Key="FoldersTemplate"
DataType="{x:Type vm:FolderViewModel}"
ItemsSource="{Binding Children}">
<Border>
<Grid>
<TextBox>
<TextBox.Style>
<Style TargetType="{x:Type TextBox}">
<Setter Property="Text" Value="{Binding Name}" />
<Style.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Text" Value="{x:Null}" />
</Trigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
</Grid>
</Border>
</HierarchicalDataTemplate>
The action I would like to happen is that when the user clicks on the text, it disappears. How can I solve this?
Thanks a lot.

WPF TextBox selected text does not work

I have a readonly TextBox control with a static resource, looks like this:
<Style TargetType="TextBox" x:Key="MyEditTextEditor">
<Setter Property="FontFamily" Value="{Binding Path=TextEditorFontFamily, ElementName=LogViewerProperty}" />
<Setter Property="FontWeight" Value="{Binding Path=TextEditorFontWeight, ElementName=LogViewerProperty}" />
<Setter Property="FontSize" Value="{Binding Path=TextEditorFontSize, ElementName=LogViewerProperty}" />
<Setter Property="FontStyle" Value="{Binding Path=TextEditorFontStyle, ElementName=LogViewerProperty}" />
<Setter Property="TextWrapping" Value="{Binding Path=WordWrapping, ElementName=LogViewerProperty, Converter={StaticResource BoolToTextWrap}}" />
<Setter Property="Text" Value="{Binding Message, Mode=OneWay}" />
<Setter Property="IsReadOnly" Value="True" />
<Setter Property="Visibility" Value="Collapsed" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<Grid>
<TextBox Text="{TemplateBinding Text}" BorderThickness="0" Margin="-3,-1"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=IsSelected, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}" Value="True">
<Setter Property="Background">
<Setter.Value>
<SolidColorBrush Opacity="0.4" Color="{Binding Source={x:Reference LogViewerProperty}, Path=TextEditorSelectionColor}" />
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
It's embedded into a ListBox. All works fine, but when I want to get the selected text, the property is always string.Empty. The SelectionChanged event works perfect. Any suggestions? At the moment I do not know, why the SelectedText is string.Empty.
Here is the SelectionChanged event
private void ReadOnlyEditor_SelectionChanged(object sender, RoutedEventArgs e)
{
LOG.Debug("Current text {3}; selection {0} length {1}, start {2}", readOnlyEditor.SelectedText, readOnlyEditor.SelectionLength, readOnlyEditor.SelectionStart, readOnlyEditor.Text);
}
And yes, the text is selected in the control, but the property is empty. In readOnlyEditor.Text exists the right text.
Put your data binding into the ListBoxItem, then call the data from the ListBoxItem. Then the whole ListBoxItem is selectable. e.g.
<ListBox SelectionChanged="ListItemSelected" ItemTemplate="{StaticResource SelectedTextTemplate}">
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem" BasedOn="{StaticResource {x:Type ListBoxItem}}">
.../...
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
Build your data template or control template outside of the ListBox e.g.
<DataTemplate x:Key="SelectedTextTemplate">
<TextBox Text="{Binding SelectedText}"/>
</DataTemplate>

Change the colour of the particular element in Treeview WPF

I have a Treeview in my WPF application. On the fly, in run time, If the element of the Tree meets certain condition, It should change its Font color from Black To Red.!
XAML
<TreeView Grid.Column="0" Grid.Row="0" HorizontalAlignment="Stretch" Name="treeView1"
VerticalAlignment="Stretch"
SelectedItemChanged="treeView1_SelectedItemChanged" HorizontalContentAlignment="Stretch"
VerticalContentAlignment="Top" BorderThickness="0,0,0,1" BorderBrush="LightGray">
<TreeViewItem Header="Head Tree" ItemsSource="{Binding MainComps}">
<TreeViewItem.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Setter Property="FontWeight" Value="Normal" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="FontWeight" Value="Bold" />
</Trigger>
<DataTrigger Binding="{Binding IsSelected}" Value="True">
<Setter Property="Foreground" Value="RED" />
</DataTrigger>
</Style.Triggers>
</Style>
</TreeViewItem.ItemContainerStyle>
<TreeViewItem.Resources>
<HierarchicalDataTemplate DataType="{x:Type TextBlock}" ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="Head Tree" />
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:MainCompViewModel}" ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Maincompname}" />
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:FeatureViewModel}" ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding FeatureName}" />
</StackPanel>
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type local:CompViewModel}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Component}" />
</StackPanel>
</DataTemplate>
</TreeViewItem.Resources>
</TreeViewItem>
</TreeView>
Code behind
private void treeView1_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
if(selected Item meets certain condition)
{
//Change color of tree node
}
}
How can I change the color of particular Node and leave it in the same color SO that when expanded again It should be in RED.
Any help would be appreciated.
You could create a boolean property in the model which is true when the elements meets the condition. Then you bind the Foreground like so:
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=BoolProp}" Value="False">
<Setter Property="Foreground" Value="Blue"></Setter>
</DataTrigger>
<DataTrigger Binding="{Binding Path=BoolProp}" Value="True">
<Setter Property="Foreground" Value="Red"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
or with converter:
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="Foreground" Value="{Binding Path=BoolProp, Converter={StaticResource ResourceKey=TheKey}}"/>
</Style>
</TreeView.ItemContainerStyle>
Just change the Foreground:
TreeViewItem ti = (TreeViewItem)treeView1.SelectedItem;
ti.Foreground = Brushes.Red;
That is embedded into the template. You can only change the color by copying the default Aero-Style for the control and changing the hard-coded value.
Or by drilling down the visual tree on-load to change it that way.
To get the default style & tenmplate go through this MSDN
Can also check step wise EXAMPLE from here.

UserControl databinding with a treeview

I have a UserControl which contains a TreeView and a TextBlock:
<TreeView ItemsSource="{Binding FirstGeneration}" AllowDrop="True" Drop="TreeView_Drop" Width="300">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Setter Property="FontWeight" Value="Normal" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="FontWeight" Value="Normal" />
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal" >
<Image Source="{Binding Path=Image}" />
<TextBlock Text="{Binding Name}" />
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<TextBlock Height="23" Name="textBlock1" Text="{Binding= ???}" Width="187" />
When I select an item of the treeview, I want do show some informations contained in the item (eg : the name of the selected item).
My problem is that I don't know how doing this binding, because when I select an item, the setter IsSelected of the item class is called.
Have you a best practice for doing that ?
Have a look at this in MSDN. And also the BindableSelectedItemBehaviour here.

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