Question

我需要在运行时基于EventInfo对象生成一个事件处理程序，并在该事件处理程序中调用一个方法。如下所示：

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);
}

我需要帮助为注释部分生成IL代码。

Answer 1

我猜你想要从你事件的MethodInfo中委托代表......

如果是这样，here is an article描述了如何解决这个问题。所需的IL代码在该文章中进行了解释。

Answer 2

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);
}

编辑：想一想，如果你的所有事件都遵循（发件人，args）模式，你甚至不需要乱用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)) ;
}

使用DynamicMethod和ILGenerator在C＃中生成动态事件

2 个答案: