c# - 如何设置 ContentPresenter 内容背景

Question

我有一个 ListBox，它绑定(bind)到动态创建的 UserControls 的 ObesvableCollection。

<ListBox x:Name="myListBox">
   <ListBox.Style>
      <Style TargetType="{x:Type ListBox}">
            <Setter Property="ItemsSource" Value="{Binding userControlsCollection}"/>
         ....
      </Style>
   </LIstBox.Style>
    <ListBox.ItemContainerStyle>
                <Style TargetType="{x:Type ListBoxItem}">
                    <EventSetter Event="Selector.Selected" Handler="ListBox_Selected"/>
                    <EventSetter Event="Selector.Unselected" Handler="ListBox_UnSelected"/>
                    <Setter Property="Background" Value="{DynamicResource DefaultBackground}" />
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="{x:Type ListBoxItem}">

                                <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                                                      VerticalAlignment="{TemplateBinding VerticalContentAlignment}" 
                                                      SnapsToDevicePixels="true"
                                                      Width="{Binding ActualWidth,RelativeSource={RelativeSource FindAncestor,AncestorType=ListBoxItem,AncestorLevel=1}}"
                                                      Height="{Binding ActualHeight,RelativeSource={RelativeSource FindAncestor,AncestorType=ListBoxItem, AncestorLevel=1}}"                                                      
                                                      />                                
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                 </Style>
</ListBox>

我想设置所选控件的背景应该是这样的

<Style.Triggers>
    <Trigger Property="IsSelected" Value="True">
        <Setter Property="Background" Value="{DynamicResource SelectedBackground}"/>
    </Trigger>
</Style.Triggers>

但是这样我设置了 ListBoxItem Background 并且它不会传播 UserControls Background...

我现在解决它的方法是像这样使用 Selector.Selected/UnSelected 事件处理程序

private void ListBox_Selected(object sender, RoutedEventArgs e)
    {

        var item = e.Source as ListBoxItem;
        var ctrl= item.Content as myControl;

        if (ctrl!= null)
        {
            ctrl.Background = new SolidColorBrush(DefaultSelectedBackground);

        }           
    }

任何想法将不胜感激

Answer 1

尽量保持 ItemContainerStyle 简单。如果您需要弄乱项目的 Template，请使用 ItemTemplate 或 RelativeSource 绑定(bind)来实现您的需要。

为了满足您对 RelativeSource 绑定(bind)的要求，我只需要像这样的 ItemContainerStyle:

<ListBox.ItemContainerStyle>
  <Style TargetType="{x:Type ListBoxItem}">
    <Setter Property="Background"
            Value="BurlyWood" />
    <Setter Property="HorizontalContentAlignment"
            Value="Stretch" />
    <Setter Property="VerticalContentAlignment"
            Value="Stretch" />
    <Style.Triggers>
      <Trigger Property="IsSelected"
                Value="True">
        <Setter Property="Background"
                Value="Tomato" />
      </Trigger>
      <Trigger Property="IsMouseOver"
                Value="True">
        <Setter Property="Background"
                Value="CadetBlue" />
      </Trigger>
    </Style.Triggers>
  </Style>
</ListBox.ItemContainerStyle>

现在要在 UserControl 中获取此 Background，我的 UserControl xaml 将如下所示:

<UserControl ...
             Background="{Binding RelativeSource={RelativeSource FindAncestor,
                                                                 AncestorType={x:Type ListBoxItem}},
                                  Path=Background}">

就是这样，我们已经排序了。

您可以从以下位置获取此演示:Here

更新:

如果您正在从代码隐藏创建 UserControl(不知道为什么您需要 但无论如何)，也要在代码隐藏中分配绑定(bind)。像这样的东西:

public UserControl CreateUserControl(string text) {
  Binding binding = new Binding {
    Path = new PropertyPath(BackgroundProperty),
    RelativeSource = new RelativeSource() {
      Mode = RelativeSourceMode.FindAncestor,
      AncestorType = typeof(ListBoxItem)
    }
  };
  var uc = new UserControl {
    Content = new TextBlock {
      Text = text,
      FontSize = 24,
      FontWeight = FontWeights.Bold,
      HorizontalAlignment = HorizontalAlignment.Center,
      VerticalAlignment = VerticalAlignment.Center
    }
  };

  BindingOperations.SetBinding(uc, BackgroundProperty, binding);
  return uc;
}

ItemContainerStyle 将保持与以前相同，您应该完成了。

此方法的演示:Here