如何删除所有Click事件处理程序

Question

可能重复：如何删除按钮的Click事件的所有事件处理程序？

我想从按钮中删除所有单击事件处理程序。我在Stack Overflow问题中找到了这个方法如何从控件中删除所有事件处理程序。

private void RemoveClickEvent(Button b)
{
    FieldInfo f1 = typeof(Control).GetField("EventClick",
                                            BindingFlags.Static |
                                            BindingFlags.NonPublic);
    object obj = f1.GetValue(b);
    PropertyInfo pi = b.GetType().GetProperty("Events",
                                              BindingFlags.NonPublic |
                                              BindingFlags.Instance);
    EventHandlerList list = (EventHandlerList)pi.GetValue(b, null);
    list.RemoveHandler(obj, list[obj]);
}

但这一行总是返回null：

  typeof(Control).GetField("EventClick", BindingFlags.Static | BindingFlags.NonPublic);

这个方法写于2006年。

这种方法有最新版本吗？

注意：我正在使用WPF和.NET 4.0。

Answer 1

下面是一个有用的实用程序方法，用于检索任何路由事件的所有订阅事件处理程序：

/// <summary>
/// Gets the list of routed event handlers subscribed to the specified routed event.
/// </summary>
/// <param name="element">The UI element on which the event is defined.</param>
/// <param name="routedEvent">The routed event for which to retrieve the event handlers.</param>
/// <returns>The list of subscribed routed event handlers.</returns>
public static RoutedEventHandlerInfo[] GetRoutedEventHandlers(UIElement element, RoutedEvent routedEvent)
{
    // Get the EventHandlersStore instance which holds event handlers for the specified element.
    // The EventHandlersStore class is declared as internal.
    var eventHandlersStoreProperty = typeof(UIElement).GetProperty(
        "EventHandlersStore", BindingFlags.Instance | BindingFlags.NonPublic);
    object eventHandlersStore = eventHandlersStoreProperty.GetValue(element, null);
    // Invoke the GetRoutedEventHandlers method on the EventHandlersStore instance 
    // for getting an array of the subscribed event handlers.
    var getRoutedEventHandlers = eventHandlersStore.GetType().GetMethod(
        "GetRoutedEventHandlers", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
    var routedEventHandlers = (RoutedEventHandlerInfo[])getRoutedEventHandlers.Invoke(
        eventHandlersStore, new object[] { routedEvent });
    return routedEventHandlers;
}

使用以上内容，您的方法的实现变得非常简单：

private void RemoveClickEvent(Button b)
{
    var routedEventHandlers = GetRoutedEventHandlers(b, ButtonBase.ClickEvent);
    foreach (var routedEventHandler in routedEventHandlers)
        b.Click -= (RoutedEventHandler)routedEventHandler.Handler;
}