如何在C ++ / CLI中转发声明一个委托？ [英] How do I forward declare a delegate in C++/CLI?

问题描述

如何？

以下操作无效：

delegate MyDelegate;
ref class MyDelegate;
delegate void MyDelegate;

以下适用于声明：

public delegate void MyDelegate(Object ^sender, MyArgs ^args);

但是使用它作为向前声明给我

But using it as a forward declaration gives me

error C3756: 'MyNameSpace::MyDelegate': delegate definition conflicts with an existing symbol

推荐答案

这项工作适合我;

stdafx.h：

public delegate void Handler(bool isit);

cli1.cpp：

#include "stdafx.h"
using namespace System;

namespace MY {
   namespace Namespace
   {
       public ref class Objeks
       {
           public: Objeks() {}
           public: event Handler^ OnHandler;
           public: void __clrcall Runner(bool checkit)
           {
              if(&Objeks::OnHandler != nullptr) 
                OnHandler(checkit);
           }
       };
   }
}

我离开了默认的VS 2010 C ++ / CLI项目在大多数情况下，我希望如果你经历前进声明的麻烦，使用命名空间System;也会在标题的另外：）

I left the default VS 2010 C++/CLI project alone for the most part, I would expect that if your going through the trouble of forward declarations, the using namespace System; would go in the header's also :)

也许你不想使用事件？但是它似乎简单的结构。

Maybe you did not want to use event? But it seems to simply the structure.

我添加了错误检查后考虑（ http://stackoverflow.com/questions/649633/error-compiling-c-cli-delegate-call ）。

I added the error check after considering (http://stackoverflow.com/questions/649633/error-compiling-c-cli-delegate-call).

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