DependencyProperty PropertyChangedCallback wiring

Question

我有一个带有UniformGrid的用户控件，它有许多按钮。我想为每个Button的Click事件分配相同的处理程序。因此，我在用户控件中添加了以下内容:

    public RoutedEventHandler GridButtonClickHandler
    {
        get { return ( RoutedEventHandler ) GetValue ( GridButtonClickHandlerProperty ); }
        set { SetValue ( GridButtonClickHandlerProperty, value ); }
    }
    public static readonly DependencyProperty GridButtonClickHandlerProperty =
        DependencyProperty.Register ( "GridButtonClickHandler", typeof ( RoutedEventHandler ), typeof ( UniformGrid ),
            new PropertyMetadata ( GridButtonClickPropertyChanged ) );
    private static void GridButtonClickPropertyChanged ( DependencyObject o, DependencyPropertyChangedEventArgs e )
    {
        ( ( UniformGrid ) o ).Children.OfType<Button> ( ).ToList ( ).ForEach ( b => b.Click += ( RoutedEventHandler ) e.NewValue );
    }

然后，在某个地方有一个对用户控件的引用(在这个例子中是numpad)，我有这样的:

numpad.GridButtonClickHandler += btn_clicked;

我有断点在GridButtonClickHandler设置和GridButtonClickPropertyChanged方法;第一个在赋值操作发生时触发，但第二个不触发。

看到我做错了什么吗?

Answer 1

您已经在UniformGrid上注册了您的依赖属性以设置处理程序，您需要一个UniformGrid实例和以下代码:

uniformGrid.SetValue(MyUserControl.GridButtonClickHandlerProperty, new RoutedEventHandler(btn_clicked));

如果它不是你的目标，并想使用它:numpad.GridButtonClickHandler += btn_clicked;，其中numpad是你的用户控制。那么owner类型应该是注册时的用户控件:

public static readonly DependencyProperty GridButtonClickHandlerProperty =
        DependencyProperty.Register ( "GridButtonClickHandler", 
        typeof ( RoutedEventHandler ), 
        typeof ( MyUserControl),
            new PropertyMetadata ( GridButtonClickPropertyChanged ) );

Answer 2

你需要一个路由事件，而不是一个依赖属性…

public static readonly RoutedEvent GridButtonClickEvent = EventManager.RegisterRoutedEvent("GridButtonClick", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(MyUserControl));
public event RoutedEventHandler GridButtonClick
{
    add { AddHandler(GridButtonClickEvent, value); }
    remove { RemoveHandler(GridButtonClickEvent, value); }
}

当按钮被点击时，引发事件:

private void GridButton_Click(object sender, RoutedEventArgs e)
{
    RaiseEvent(new RoutedEventArgs(GridButtonClickEvent, this));
}