How to add a StringFormat to a Textblock inside a DataTemplate?

Question

I have the following DataTemplate:

<DataTemplate x:Key="ColoringLabels">
    <TextBlock Padding="0"
               Margin="0"
               Name="Username"
               Text="{Binding Username}"
               Foreground="Gray"
               FontStyle="Italic"
              />
    <DataTemplate.Triggers>
        <DataTrigger Binding="{Binding IsLoggedIn}" Value="True">
            <Setter TargetName="Username" Property="FontSize" Value="14"/>
            <Setter TargetName="Username" Property="Foreground" Value="Green"/>
            <Setter TargetName="Username" Property="FontStyle" Value="Normal"/>
        </DataTrigger>
    </DataTemplate.Triggers>
</DataTemplate>

I would like to use the template in a ListView where every username is followed by a ; and a space.

Effectively the template would then behave as it were written like this:

<DataTemplate x:Key="ColoringLabels">
    <TextBlock Padding="0"
               Margin="0"
               Name="Username"
               Text="{Binding Username, StringFormat='{}{0}; '}"
               Foreground="Gray"
               FontStyle="Italic"
              />
    <DataTemplate.Triggers>
      ...
    </DataTemplate.Triggers>
</DataTemplate>

How can I extend the original template to get the result of the second one?

Branchiopod

Not sure what the crux of your question is. Is it about the StringFormat part, or is it about extending an existing template to get a new one? You've received an answer to either one :-) – Lactic

Answer 1

There isn't a direct mechanism to have one DataTemplate inherit the properties of another one.

However, you can succesfully avoid code duplication by using styles, which DO have inheritance capabilities.

I believe this would give you what you need:

    <Style x:Key="StandardBoundTb" TargetType="TextBlock">
        <Setter Property="Padding" Value="0" />
        <Setter Property="Margin" Value="0" />
        <Setter Property="Text" Value="{Binding Path=Username}" />
        <!-- etc -->
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=IsLoggedIn}" Value="True">
                <Setter Property="FontSize" Value="14" />
                <!-- etc -->
            </DataTrigger>
        </Style.Triggers>
    </Style>
    <Style x:Key="DelimitedBoundTb" TargetType="TextBlock" 
           BasedOn="{StaticResource StandardBoundTb}"
    >
        <Setter Property="Text" Value="{Binding Path=Username, StringFormat='{}{0}; '}" />
    </Style>

    <DataTemplate x:Key="ColoringLabels">
        <TextBlock Style="{StaticResource StandardBoundTb}" />
    </DataTemplate>
    <DataTemplate x:Key="ColoringLabelsDelimited">
        <TextBlock Style="{StaticResource DelimitedBoundTb}" />
    </DataTemplate>

Lactic

Wonderful, should have found it myself. But SO provides excellent answers so fast that I become lazy... – Branchiopod