We Keep Coding

ContentStringFormat never changes by Setter Property in DataTrigger

In my user control I want to have label displaying Text from resource depending on viewmodel property Location value and with different format.
I implemented it by defining DataTrigger for each Location value
<Style x:Key="LocationValueHelper" TargetType="{x:Type Label}">
<Style.Triggers>
<DataTrigger Binding="{Binding Location}" Value="HomeViewModel">
<Setter Property="Content" Value="" />
<Setter Property="ContentStringFormat" Value="{}{0}???"/>
</DataTrigger>
<DataTrigger Binding="{Binding Location}" Value="FirstViewModel">
<Setter Property="ContentStringFormat" Value="{}{0}+++"/>
<Setter Property="Content" Value="{localization:LanguageResource ResourceKey=First}" />
</DataTrigger>
<DataTrigger Binding="{Binding Location}" Value="SecondViewModel">
<Setter Property="ContentStringFormat" Value="{}{0}---"/>
<Setter Property="Content" Value="{localization:LanguageResource ResourceKey=Second}" />
</DataTrigger>
<DataTrigger Binding="{Binding Location}" Value="ThirdViewModel">
<Setter Property="ContentStringFormat" Value="{}{0}***"/>
<Setter Property="Content" Value="{localization:LanguageResource ResourceKey=Third}" />
</DataTrigger>
</Style.Triggers>
</Style>
<Label Foreground="White" HorizontalAlignment="Center" FontSize="40" Style="{StaticResource LocationValueHelper}" />
The problem is that format never changes from the first one (???) - HomeViewModel selected first - although text changing works.
I have
Home???
First???
Second???
Third???
instead of
Home???
First+++
Second---
Third***

There are a lot of discussions, using Labels and ContentStringFormat does not work like expected or desired:
WPF StringFormat on Label Content
StringFormat VS ContentStringFormat
...
The reason seems to be the template based implementation under the hood, since the content also could contain other data than strings. To solve your problem, my proposal is to use a TextBlock, which works quite smooth like this:
<StackPanel>
<CheckBox IsChecked="{Binding MyFlag}"/>
<TextBlock HorizontalAlignment="Center" FontSize="40">
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding MyFlag}" Value="False">
<Setter Property="Text" Value="{Binding Path=MyText, StringFormat='{}{0}+++'}" />
</DataTrigger>
<DataTrigger Binding="{Binding MyFlag}" Value="True">
<Setter Property="Text" Value="{Binding Path=MyText, StringFormat='{}{0}???'}" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</StackPanel>

How to bind to a SelectedValue data context property in WPF?

I have a listbox that display some model items.
I would like to hide some control below the listbox based on the boolean value of the model item associated with the selected listbox item.
I tried the following but it did not work:
1) set the ListBox SelectedValuePath="MyModelBooleanProperty"
2) add a data trigger to the control that I want to hide as follows
<DataTrigger Binding="{Binding ElementName=FolderList, Path=SelectedValue}" Value="False">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=FolderList, Path=SelectedValue}" Value="True">
<Setter Property="Visibility" Value="Visible"></Setter>
</DataTrigger>

I used this and it worked. Also make sure you don't explicitly set Visibility of TextBlock that overrides whatever the Style does.
<ListBox
x:Name="FolderList"
ItemsSource="{Binding Source={StaticResource ViewModel}, Path=List}"
SelectedValuePath="SomeBooleanProperty">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding SomeStringProperty}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<TextBlock>
<TextBlock.Style>
<Style TargetType="TextBlock">
<Setter Property="Visibility" Value="Visible" />
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=FolderList, Path=SelectedValue}" Value="False">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=FolderList, Path=SelectedValue}" Value="True">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
My Text Block
</TextBlock>

wpf button command binding after trigger the propery changes

i have a button in my wpf form and the button is having the image text in mvvm application when i click the button it will attach the file, my requirement is when it attached successfully the text is changed to Approve , I want to write another command propery for this command after changed the text to Approve.
<Button ToolTip="Attach Approval"
Height="25"
Command="{Binding AddAttachmentCommand}"
Margin="5,10,5,10">
<Button.Style>
<Style TargetType="{x:Type Button}">
<!-- Default Content value -->
<Setter Property="Content">
<Setter.Value>
<StackPanel Orientation="Horizontal">
<Image Source="/UILibrary;component/Themes/Default/Images/Attach.PNG"/>
</StackPanel>
</Setter.Value>
</Setter>
<!-- Triggered values -->
<Style.Triggers>
<DataTrigger Binding="{Binding IsAttachmentAvailable}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
<Setter Property="Content" Value="Appprove"/>
</DataTrigger>
<DataTrigger Binding="{Binding IsAttachmentAvailable}" Value="False">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>

If you want to change a property (in your case the Command) in a trigger, you have to initialise the property in the style setter. To make your code work remove the command property from the button and add the command property to the style setter.
<Button ToolTip="Attach Approval"
Height="25"
Margin="5,10,5,10">
<Button.Style>
<Style TargetType="{x:Type Button}">
<!-- Default Content value -->
<Setter Property="Command" Value="{Binding AddAttachmentCommand}"/>
<Setter Property="Content">
<Setter.Value>
<StackPanel Orientation="Horizontal">
<Image Source="/UILibrary;component/Themes/Default/Images/Attach.PNG"/>
</StackPanel>
</Setter.Value>
</Setter>
<!-- Triggered values -->
<Style.Triggers>
<DataTrigger Binding="{Binding IsAttachmentAvailable}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
<Setter Property="Content" Value="Appprove"/>
<Setter Property="Command" Value="SOME OTHER COMMAND"/>
</DataTrigger>
<DataTrigger Binding="{Binding IsAttachmentAvailable}" Value="False">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>

Datatrigger on empty string

How can a DataTrigger change the visibility of stackpanel, based on a binded string?
I have the following Xaml
<StackPanel HorizontalAlignment="Right"
Orientation="Horizontal"
Grid.Column="1"
Background="#FF7a7a7a">
<StackPanel.Style>
<Style TargetType="{x:Type StackPanel}">
<Style.Triggers>
<DataTrigger Binding="{Binding SearchText}" Value="">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</StackPanel.Style>
Content....
</StackPanel>
I Know that SearchText gets updates and binds properly outside the StackPanel
Could somebody point me in the right direction?

This:
<DataTrigger Binding="{Binding SearchText}" Value="">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
will work for empty string (""), however it will not work for null.
Add another DataTrigger for the null case:
<DataTrigger Binding="{Binding SearchText}" Value="{x:Null}">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>

Correct using String.Empty in XAML:
xmlns:sys="clr-namespace:System;assembly=mscorlib"
...
<DataTrigger Binding="{Binding SearchText}" Value="{x:Static sys:String.Empty}">

Weird as it might sound, the code below works for me:
<StackPanel Background="#FF7a7a7a">
<StackPanel.Style>
<Style TargetType="{x:Type StackPanel}">
<Style.Triggers>
<DataTrigger Binding="{Binding Text, ElementName=textBlock}" Value="">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</StackPanel.Style>
<TextBox x:Name="textBlock" Text="" Width="100" Height="30"></TextBox>
</StackPanel>
Can you tell the value your Property is sending?

Try this
<StackPanel.Style>
<Style TargetType="StackPanel">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger Binding="{Binding YourBoundPropertyName}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</StackPanel.Style>

Calling a Image style

Is there any way to create a call'able image style? I have multiple buttons on a user control that have the same button and button image style. I can set the button style so that it can be called from the style (dynamic resource) of the button.
Here is an example of my code and the image style code:
<Grid.Resources>
<Style TargetType="Button"
x:Key="ButtonEditSaveStyle">
<Setter Property="IsEnabled"
Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding CanEdit}"
Value="True">
<Setter Property="IsEnabled"
Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
</Grid.Resources>
<Button Width="32"
Height="22"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Name="gdEmployeeInfo_btnUpdateRecord"
Click="gdEmployeeInfo_btnUpdateRecord_Click"
Style="{DynamicResource ResourceKey=ButtonEditSaveStyle}"/>
I want to set my code up so that I can have the call above an have an additional call or a combined call to set the image style as well. I know I can have the image style in the button (as shown in this next code), but I want to have one place to update multiple buttons using the same style setup. Image style code:
<Image>
<Image.Style>
<Style TargetType="{x:Type Image}">
<Setter Property="Source"
Value="edit_32.png" />
<Setter Property="Stretch"
Value="Uniform" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsEditing}"
Value="True">
<Setter Property="Source"
Value="save_smallest.png" />
<Setter Property="Stretch"
Value="Uniform" />
</DataTrigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>

Figured out the answer to my question. This set of code allows me to use dual style setting while creating only one call for the button's style:
<!--SaveEditImageSwitch-->
<Image x:Key="SaveEditImage" x:Shared="False">
<Image.Style>
<Style TargetType="{x:Type Image}">
<Setter Property="Source"
Value="edit_32.png" />
<Setter Property="Stretch"
Value="Uniform" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsEditing}"
Value="True">
<Setter Property="Source"
Value="save_smallest.png" />
<Setter Property="Stretch"
Value="Uniform" />
</DataTrigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>
<!--ButtonEditSaveStyle-->
<Style TargetType="Button"
x:Key="ButtonEditSaveStyle">
<Setter Property="IsEnabled"
Value="False" />
<Setter Property="Content"
Value="{DynamicResource ResourceKey=SaveEditImage}" />
<Style.Triggers>
<DataTrigger Binding="{Binding CanEdit}"
Value="True">
<Setter Property="IsEnabled"
Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
<Button Width="32"
Height="22"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Name="gdEmployeeInfo_btnUpdateRecord"
Click="gdEmployeeInfo_btnUpdateRecord_Click"
Style="{DynamicResource ResourceKey=ButtonEditSaveStyle}">