WPF自定义控件中如何将ToggleButton事件绑定到传入的ICommand？

我为应用创建了一个WPF自定义控件WindowHeader，目前需要给控件内的ToggleButton关联事件逻辑。已在WindowHeader.cs中定义了TargetSelectedCommand依赖属性，在WindowHeader.xaml的控件模板里，ToggleButton绑定了PreviewMouseDown等事件，希望在Target_PreviewMouseDown触发时，执行通过WindowHeader传入的TargetSelectedCommand命令。相关代码如下：

WindowHeader.cs #

public class WindowHeader : ContentControl 
{
    public static readonly DependencyProperty TargetSelectedCommandProperty = 
        DependencyProperty.Register(nameof(TargetSelectedCommand), typeof(ICommand), typeof(WindowHeader));   

    public ICommand TargetSelectedCommand
    {
        get => (ICommand)GetValue(TargetSelectedCommandProperty);
        set => SetValue(TargetSelectedCommandProperty, value);
    }
}

WindowHeader.xaml #

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:ctrl="clr-namespace:App.Windows.Lib.CustomControls"
                    x:Class="App.Windows.Lib.Style.CustomControls.WindowHeader"
                    x:ClassModifier="public">

  <Style TargetType="{x:Type ctrl:WindowHeader}">

    <Setter Property="Template">

      <Setter.Value>

        <ControlTemplate TargetType="{x:Type ctrl:WindowHeader}">

          <ctrl:DragArea>

          <Grid>
            <Grid.ColumnDefinitions>
              <ColumnDefinition Width="*" />
              <ColumnDefinition Width="Auto" />
            </Grid.ColumnDefinitions>

          <TextBlock Grid.Column="0"
                     Style="{DynamicResource TargetSelection_TextBlock}"
                     Text="{TemplateBinding SelectedTargetName}"
                     Visibility="{TemplateBinding ShowTargeting}"/>

            <StackPanel Grid.Column="1"
                        Style="{DynamicResource WindowHeader_StackPanel}">

                <ToggleButton PreviewMouseDown="Target_PreviewMouseDown" 
                              PreviewMouseUp="Target_PreviewMouseUp"
                              Style="{DynamicResource Target_Button}"
                              Visibility="{TemplateBinding ShowTargeting }" />

                <ToggleButton Click="Pin_Click"
                              Style="{DynamicResource Pin_Button}"
                              Visibility="{TemplateBinding ShowPinning}" />

               <ToggleButton Click="Resize_Click"
                             Style="{DynamicResource Resize_Button}"
                             Visibility="{TemplateBinding ShowResizing}"/>
              
            </StackPanel>

          </Grid>

          </ctrl:DragArea>

        </ControlTemplate>
        
      </Setter.Value>
      
    </Setter>
    
  </Style>
</ResourceDictionary>

WindowHeader.xaml.cs #

public partial class WindowHeader : ResourceDictionary 
{
    public WindowHeader() 
    { 
        InitializeComponent(); 
    } 
        
    public void Target_PreviewMouseDown(object sender, MouseButtonEventArgs e)
    {
        // 此处需要获取传入WindowHeader的TargetSelectedCommand并执行
        throw new NotImplementedException();
    }
    
    public void Target_PreviewMouseUp(object sender, MouseButtonEventArgs e)
    {
        throw new NotImplementedException();
    }
}

MainWindow.xaml控件声明 #

<ctrl:WindowHeader TargetSelectedCommand="{Binding OutputDestinationViewModel.DestinationSelectedCommand}" />

解决方案 #

方法一：通过TemplatedParent获取控件实例执行命令 #

在事件处理方法中，通过ToggleButton的TemplatedParent找到对应的WindowHeader实例，进而获取并执行命令：

public void Target_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    var toggleButton = sender as ToggleButton;
    if (toggleButton == null) return;

    // 获取模板关联的WindowHeader控件实例
    var windowHeader = toggleButton.TemplatedParent as WindowHeader;
    if (windowHeader?.TargetSelectedCommand != null && windowHeader.TargetSelectedCommand.CanExecute(null))
    {
        // 如需传递参数，将null替换为对应参数即可
        windowHeader.TargetSelectedCommand.Execute(null);
    }
}

方法二：直接在XAML中绑定Command（更符合MVVM） #

如果不需要额外的鼠标事件逻辑，可以直接在ToggleButton上绑定命令，省去事件中转步骤：

<ToggleButton Command="{TemplateBinding TargetSelectedCommand}"
              Style="{DynamicResource Target_Button}"
              Visibility="{TemplateBinding ShowTargeting }" />

注意事项 #

• 确保TargetSelectedCommand的CanExecute逻辑正确，执行命令前先判断是否可执行。
• 控件模板的TargetType必须正确设置为ctrl:WindowHeader，否则TemplateBinding无法解析依赖属性。

内容的提问来源于stack exchange，提问作者Richard Gale