ListBoxItem模板中控件样式的相对绑定

Question

My problem is with the following code, with binding the IsAvailable property of the MyListBoxItem class. My current solution:

<ListBox ItemTemplate="{StaticResource myTemplate}">
  <ListBox.Resources>
    <DataTemplate x:Key="myTemplate" DataType="{x:Type local:MyListBoxItem}">
      <Label Foreground="Green" Content="{Binding Title}" Tag="{Binding IsAvailable}">
        <Label.Style>
          <Style TargetType="{x:Type Label}">
            <Style.Triggers>
              <DataTrigger Binding="{Binding Tag, RelativeSource={RelativeSource Self}}" Value="True">
                <Setter Property="FontWeight" Value="Bold"/>
              </DataTrigger>
            </Style.Triggers>
          </Style>
        </Label.Style>
      </Label>
    </DataTemplate>
    ... (more datatemplates)

  </ListBox.Resources>
</ListBox>

My question: In my solution the value of IsAvailable "goes through" two bindings. The first one binds the value to the Tag property of the Label and then in the style triggers, a trigger checks its value and sets a property of the Label . When I used Binding="{Binding IsAvailable, RelativeSource={RelativeSource AncestorType={x:Type local:MyListBoxItem}}}" it didn't work, because the Style can't see any ancestor of the Label (or something similar reason), it resulted binding errors (with code 4 or 40 maybe), for each item added to the ListBox .

So finally: can I make the solution more simple, or there is no another (better) one?

An important thing I've forgot to mention, sorry : I put the DataTemplate in the ListBox's resources because I have more templates (they are basically differ, so I can't style them with triggers), which I have to switch between sometimes...

Answer 1

The ItemTemplate will take the type that the ItemsSource is bound to. Therefore you should be able to simply bind to IsAvailable , as the ListBox's item type is MyListBoxItem . Try this:

<ListBox ItemsSource="...">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Label Foreground="Green" Content="{Binding Title}" Tag="{Binding IsAvailable}">
                    <Label.Style>
                        <Style TargetType="{x:Type Label}">
                            <Style.Triggers>
                                <DataTrigger Binding="{Binding Tag, RelativeSource={RelativeSource Self}}" Value="True">
                                    <Setter Property="FontWeight" Value="Bold"/>
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </Label.Style>
                </Label>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

You'll need to set your ItemsSource property to a Binding to the MyListBoxItem collection.