Question

public class AwaitableRoutedEvent
{
    private TaskCompletionSource<object> _tcs;

    public async Task When<TypeOfControl>(TypeOfControl source, string nameOfEvent)
    {
        _tcs = new TaskCompletionSource<object>();

        var targetEventInfo = source.GetType().GetEvent(nameOfEvent);
        Delegate tempEventHandler =
            Delegate.CreateDelegate(
                targetEventInfo.EventHandlerType,
                GetType().GetMethod(nameof(RoutedEventHandler), BindingFlags.Instance | BindingFlags.Public));

        try
        {
            targetEventInfo.AddEventHandler(source, tempEventHandler);

            await _tcs.Task;
        }
        finally
        {
            targetEventInfo.RemoveEventHandler(source, tempEventHandler);
            _tcs = null;
        }
    }

    public void RoutedEventHandler(object sender, RoutedEventArgs arguments)
    {
        _tcs.TrySetResult(null);
    }
}

上面的calss表示'等待'RoutedEventHandler事件。目标是像await new AwaitableRoutedEvent().When(button_object, "click");一样使用它。

如果我制作public void RoutedEventHandler(object sender, RoutedEventArgs arguments)静态 ...并更改BindingsFlags ......就可以了。但我不喜欢静电。非静态版本引发异常：Cannot bind to the target method because its signature or security transparency is not compatible with that of the delegate type。

我错过了什么吗？

Answer 1

因为RoutedEventHandler是一个实例方法，所以在创建委托时，您应该提供调用该方法的对象的实例：

> /var/log/sshd.log format=raw
? [= Facility auth] file sshd.log

看起来你根本不需要它，因为你可能会写

Delegate tempEventHandler =
        Delegate.CreateDelegate(
            targetEventInfo.EventHandlerType,
            this,
            GetType().GetMethod(nameof(RoutedEventHandler), BindingFlags.Instance | BindingFlags.Public));

无法绑定到目标方法，因为...来自Delegate.Create（..）+ Reflection

1 个答案: