使用DynamicMethod的和动态的ILGenerator事件发生在C＃

Question

我需要生成基于在运行时EventInfo对象的事件处理程序，并调用该事件处理程序中的方法。类似如下：

public void RegisterAction(ActionData actionData, EventInfo eventInfo, 
    Control control)
{
    MethodInfo methodInfo = eventInfo.EventHandlerType.GetMethod("Invoke");

    List<Type> ps = new List<Type>();
    foreach (ParameterInfo info in methodInfo.GetParameters())
    {
        ps.Add(info.ParameterType);
    }

     DynamicMethod method = new DynamicMethod("Adapter",
                                              typeof (void),
                                              ps.ToArray(),
                                              GetType(), 
                                              true);

     ILGenerator generator = method.GetILGenerator();

     // Here I need to generate a method to do the following:
     // ExecuteAction(actionData);

     // Then I can use this runtime method as an event handler and
     // bind it to the control
     Delegate proxy = method.CreateDelegate(eventInfo.EventHandlerType, this);

     eventInfo.AddEventHandler(control, proxy);
}

我需要在产生IL代码的注释部分帮助。

Answer 1

public void RegisterAction(ActionData actionData, EventInfo eventInfo, 
    Control control)
{
    MethodInfo methodInfo = eventInfo.EventHandlerType.GetMethod("Invoke");

    List<Type> ps = new List<Type>();
    ps.Add  (typeof (ActionData)) ;
    foreach (ParameterInfo info in methodInfo.GetParameters())
    {
        ps.Add(info.ParameterType);
    }

     DynamicMethod method = new DynamicMethod("Adapter",
                                              typeof (void),
                                              ps.ToArray(),
                                              GetType(), 
                                              true);

     // compatible signatures for ExecuteAction
     // (assuming you aren't interested in sender and eventArgs):
     // static void ExecuteAction (ActionData) ;
     // void ActionData.ExecuteAction () ;
     MethodInfo miExecuteAction = <...> ;
     ILGenerator generator = method.GetILGenerator();
     generator.Emit (OpCodes.Ldarg_0) ;
     generator.Emit (OpCodes.Call, miExecuteAction) ;
     generator.Emit (OpCodes.Ret) ;

     // if you want to pass this to ExecuteAction, 
     // you'll need to put it into actionData.
     Delegate proxy = method.CreateDelegate(eventInfo.EventHandlerType, actionData);

     eventInfo.AddEventHandler(control, proxy);
}

修改：现在想想看，如果你所有的活动遵循（发件人，参数）模式，你甚至不需要做乱用SRE：

public static void Execute<T> (ActionData data, object sender, T args)
    where T : EventArgs
{
    ExecuteAction (data) ;
}

public void RegisterAction (ActionData actionData, EventInfo eventInfo, 
    Control control)
{
    MethodInfo compatibleMethod = typeof (this).GetMethod ("Execute",
        BindingFlags.Static | BindingFlags.Public).MakeGenericMethod (
        eventInfo.EventHandlerType.GetMethod ("Invoke").GetParameters ()[1].ParameterType)) ;
    eventInfo.AddEventHandler (control, 
        Delegate.CreateDelegate (eventInfo.EventHandlerType, actionData,
        compatibleMethod)) ;
}

Answer 2

我猜你想从您的活动的MethodInfo作出委托...

如果这样，这里是描述如何的制品去这个问题。所需的IL代码的文章中进行了说明。