在发生泛型事件时调用方法

Question

当我试图实现对应该在运行时定义的事件触发的方法的调用时，我遇到了一个问题。我找到了这个答案：

从通用事件处理程序重定向到动态方法

并实现了该解决方案，但当要调用的方法是实例方法而不是静态方法时，我总是得到一个异常。这是我的部分代码：

public class Operation
{
    public bool EventFired 
    {
        get { return _eventFired; }
    }
    private bool _eventFired = false;
    public void Execute(object source, string EventName)
    {
        EventInfo eventInfo = source.GetType().GetEvent(EventName);
        Delegate handler = null;
        Type delegateHandler = eventInfo.EventHandlerType;
        MethodInfo invokeMethod = delegateHandler.GetMethod("Invoke");
        ParameterInfo[] parms = invokeMethod.GetParameters();
        Type[] parmTypes = new Type[parms.Length];
        for (int i = 0; i < parms.Length; i++)
            parmTypes[i] = parms[i].ParameterType;
        DynamicMethod customMethod = new DynamicMethod
            (
            "TempMethod",
            invokeMethod.ReturnType,
            parmTypes,
            typeof (Operation).Module
            );
        MethodInfo inf = typeof (Operation).GetMethod("SetFlag", BindingFlags.Instance | BindingFlags.Public);
        ILGenerator ilgen = customMethod.GetILGenerator();
        ilgen.Emit(OpCodes.Ldarg_0);
        ilgen.Emit(OpCodes.Call, inf);
        ilgen.Emit(OpCodes.Ret);
        //handler = _customMethod.CreateDelegate(delegateHandler);          // This works if I change SetFlag() to static 
        handler = customMethod.CreateDelegate(delegateHandler, this);       // I get an ArgumentException at this point: 
                                                                            //Cannot bind to the target method because its signature 
                                                                            //or security transparency is not compatible with that of the delegate type.   

        eventInfo.AddEventHandler(source, handler);
    }
    /// <summary>Signals that the event has been raised.</summary>
    public void SetFlag()
    {
        _eventFired = true;
    }
}

我找不到摆脱该异常的方法，如果我将SetFlag（）方法转为静态，代码会正常工作，但这不是我需要的。如有任何建议，我们将不胜感激。提前谢谢。

Answer 1

我最终通过稍微修改DynamicMethod定义解决了这个问题，如以下答案所述：

参考'；这'；在动态事件处理程序中

如果我将我的类类型添加为type数组中的第一个值，然后将其作为参数传递给DynamicMethod，则会正确创建委托，并且它可以与实例方法一起使用！

public class Operation
{
    public bool EventFired 
    {
        get { return _eventFired; }
    }
    private bool _eventFired = false;
    public void Execute(object source, string EventName)
    {
        EventInfo eventInfo = source.GetType().GetEvent(EventName);
        Delegate handler = null;
        Type delegateHandler = eventInfo.EventHandlerType;
        MethodInfo invokeMethod = delegateHandler.GetMethod("Invoke");
        ParameterInfo[] parms = invokeMethod.GetParameters();
        Type[] parmTypes = new Type[parms.Length + 1];
        parmTypes[0] = this.GetType();  //First parameter is this class type.
        for (int i = 0; i < parms.Length; i++)
            parmTypes[i + 1] = parms[i].ParameterType;
        DynamicMethod customMethod = new DynamicMethod
                                    (
                                        "TempMethod",
                                        invokeMethod.ReturnType,
                                        parmTypes
                                    );
        MethodInfo inf = typeof (Operation).GetMethod("SetFlag", BindingFlags.Instance | BindingFlags.Public);
        ILGenerator ilgen = customMethod.GetILGenerator();
        ilgen.Emit(OpCodes.Ldarg_0);
        ilgen.Emit(OpCodes.Call, inf);
        ilgen.Emit(OpCodes.Ret);
        handler = customMethod.CreateDelegate(delegateHandler, this);      
        eventInfo.AddEventHandler(source, handler);
    }
    /// <summary>Signals that the event has been raised.</summary>
    public void SetFlag()
    {
        _eventFired = true;
    }
}