函数指针作为COM方法的参数 [英] Function pointer as a parameter of COM method

问题描述

我在C ++中创建了使用C＃应用程序的COM服务器。现在我必须添加一个方法到我的COM对象，其中一个参数必须是函数指针回调函数。 C ++原函数看起来像这样：

I have created COM server in C++ that is used from C# application. Now I have to add one more method to my COM object and one of its parameter must be function pointer to callback function. C++ original function looks like this:

typedef int (__stdcall *tCallBackFunc)(int Param);

void MyFunc(void* CallBackFunc)
{
  int Param;
  //some code
  ((tCallBackFunc)(CallBackFunc))(Param); //call callback function
}

我需要添加MyFunc作为COM对象方法。 VS VC ++添加方法对话框提供一些预定义类型的COM方法参数像int *或bstr，我试图定义CallBackFunc参数作为int *类型，但我不能使其工作C＃：

I need to add MyFunc as COM object method. VS VC++ "Add Method" dialog offers some predefined types for COM method parameter like "int*" or "bstr", I tried to define "CallBackFunc" parameter as "int*" type, but I was not able to make it work in C#:

public delegate int  tCallBackFunc(int Param);
...
tCallBackFunc cb; //I will initialize it when it is compiled
MyCOMObject.MyFunc(cb); //cannot find any way to cast cb to "ref int"

看来我使用错误的方法，有没有一种快速的方法来声明函数指针作为C ++中COM对象方法的参数，然后在C＃中使用它？

It seems I use wrong approach, is there a fast way to declare function pointer as parameter of COM object method in C++ and then use it in C#?

推荐答案

COM方式是使参数成为一个接口指针，并让接口声明回调函数。

The COM way is to make the parameter an interface pointer, and have the interface declare the callback function.

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