R – WPF Trigger for IsSelected in a DataTemplate for ListBox items with Blend

datatemplateexpression-blendlistboxwpf

I wanted to change the Foreground color when I selected a listboxItem and I did it using this bit of code:

<DataTrigger Binding="{Binding  
RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}},Path=IsSelected}" Value="True">
                            <Setter TargetName="descriptionTB" Property="Foreground" Value="#000"/>
</DataTrigger>

You can find the answer here.

But if I want a designer to do this in Blend, how would he do it without drilling into xaml?

Thank you

Best Answer

Artur,

The Triggers designer in Expression Blend only allows adding and modifying EventTriggers and Property triggers. I haven't found a way to add DataTriggers with Blend. I'm also not sure how to set RelativeSource Binding using Blend either. I've always handed code the XAML for test and use Blend for everything else.

Related Solutions

WPF Trigger for IsSelected in a DataTemplate for ListBox items

You can style your ContentControl such that a trigger fires when its container (the ListBoxItem) becomes selected:

<ContentControl 
    x:Name="designerContent"
    MinHeight="100"
    Margin="2,0,2,2"
    Content="{Binding Path=DesignerInstance}"
    Background="#FF999898">
    <ContentControl.Style>
        <Style TargetType="{x:Type ContentControl}">
            <Setter Property="Visibility" Value="Collapsed"/>
            <Style.Triggers>
                <DataTrigger
                        Binding="{Binding
                            RelativeSource={RelativeSource
                                Mode=FindAncestor,
                                AncestorType={x:Type ListBoxItem}},
                                Path=IsSelected}"
                        Value="True">
                    <Setter Property="Visibility" Value="Visible"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ContentControl.Style>
</ContentControl>

Alternatively, I think you can add the trigger to the template itself and reference the control by name. I don't know this technique well enough to type it from memory and assume it'll work, but it's something like this:

<DataTemplate x:Key="ScenarioItemTemplate">
    <DataTemplate.Triggers>
        <DataTrigger
                Binding="{Binding
                    RelativeSource={RelativeSource
                        Mode=FindAncestor,
                        AncestorType={x:Type ListBoxItem}},
                        Path=IsSelected}"
                Value="True">
            <Setter
                TargetName="designerContent"
                Property="Visibility"
                Value="Visible"/>
        </DataTrigger>
    </DataTemplate.Triggers>

    ...
</DataTemplate>

.net – WPF listbox empty datatemplate

I've had some success with this code:

<Style TargetType="ListBox" x:Key="ListStyle" BasedOn="{StaticResource {x:Type ListBox}}">
    <Style.Triggers>
        <DataTrigger 
            Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Items.Count}" 
            Value="0"
            >
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate>
                        <TextBlock>No items to display</TextBlock>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </DataTrigger>
    </Style.Triggers>
</Style>

Best Answer

Related Solutions

WPF Trigger for IsSelected in a DataTemplate for ListBox items

.net – WPF listbox empty datatemplate

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