WPF定制路由事件 - 如何取消订阅？

问题描述

如何从一个自定义路由事件中注销

How to DeRegister from one Custom Routed Event.

我有以下代码（自定义路由事件非常标准）

I have the following code (very standard for Custom Routed Events)

//Dispatch the Video Detection Movements
public delegate void MovementRoutedEventHandler( object sender
                                                , MovementRoutedEventArgs e);
public class MovementRoutedEventArgs : RoutedEventArgs
{
    private readonly DahuaDevice _device;
    private readonly byte[] _canals;
    private readonly DateTime _when;

    public MovementRoutedEventArgs(DahuaDevice device, byte[] canals, DateTime when)
    {
        _device = device;
        _canals = canals;
        _when = when;
    }
    public DahuaDevice Device
    {
        get { return _device; }
    }
    public Byte[] Canals
    {
        get { return _canals; }
    }
    public DateTime When
    {
        get { return _when; }
    }
}
public static RoutedEvent MovementEvent = EventManager.RegisterRoutedEvent(
        "Movement"
    , RoutingStrategy.Tunnel
    , typeof(MovementRoutedEventHandler)
    , typeof(Window)
);

public event RoutedEventHandler Movement
{
    add { AddHandler(MovementEvent, value); }
    remove { RemoveHandler(MovementEvent, value); }
}
public void RaiseMovementEvent(DahuaDevice device, byte[] canals, DateTime when)
{
    RaiseEvent(new MovementRoutedEventArgs(device, canals, when)
    {
        RoutedEvent = MovementEvent
    });
}

现在一个类将用这一行订阅这个事件：

Now a class will subscribe to this event with this line:

//Receive the Movement events
EventManager.RegisterClassHandler(
      typeof(Window)
    , Main.MovementEvent
    , new Main.MovementRoutedEventHandler(MovementHandler));

当我关闭类实例时，我应该从事件中取消订阅（否则，实例不会垃圾收集）。

When I close the class instance, I should UnSubscribe from the event (otherwise, instance won't be garbage collected).

我应该叫什么？我试过 RegisterClassHandler（typeof（Window），Main.MovementEvent，** null **）但是我收到一个例外...

What should I call? I tried RegisterClassHandler(typeof(Window), Main.MovementEvent, **null**) but I get an exception...

任何帮助欢迎。感谢提前。

Any help welcome. Thanks in advance.

JM

推荐答案

您可以使用 RemoveHandler 方法来自UIElement类）

You can use RemoveHandler method from System.Windows.Window class (generally from UIElement class).

代码可能如下所示：

Main.RemoveHandler( Main.MovementEvent
                  , new Main.MovementRoutedEventHandler(MovementHandler));

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