想要从“C ++ COM dll”回调C＃方法 [英] Want to callback C# method from "C++ COM dll"

问题描述

我想从C ++ COM dll回调C＃方法，这是我采取的策略。



步骤1：在C ++中 idl中的Server.dll 我声明了2级Class1和Class2，如下所示。

I want to callback C# method from "C++ COM dll", Here is the strategy I took.

Step 1:In C++ Server.dll in idl I declared 2 class Class1 and Class2 as below.

[
       object,
       uuid(54120D45-09DE-4e61-AA30-858CE4C472B5),
       oleautomation,
       helpstring("Class1 Interface"),
       pointer_default(unique)
    ]
    interface IClass1 : IUnknown
    {
      [helpstring("GetCls2Ptr")] HRESULT GetClass2InterfacePtr(IClass2 * ptrCls);
      [helpstring("SayHellow")] HRESULT SayHellow();
    }
    interface IClass2 : IUnknown
    {
      [helpstring("CallMe")] HRESULT CallMe();
    }
    
    In Class1.h
    class Class1 :public IClass1 
    {
      IClass2 **class2Obj;
     STDMETHOD GetClass2InterfacePtr(IClass2 * ptrCls)
      {
        class2Obj= (&ptrCls);
        return S_OK;
      }
    STDMETHOD SayHellow(void)
      {
       (*class2Obj)->CallMe();
       return S_OK;
      }
    }

第2步：

Step 2:

TlbImp c:\Server.tlb to generate Managed dll [ServerManaged.dll].

步骤3：

Step 3:

refer ServerManaged.dll in C# 

步骤4：

Step 4:

In C# I declared 1 class as below

using ServerManaged;
namespace Test1
{
public class CSClass : IClass2
{
  IClass1 IClass1Obj=null;
  public CSClass()
  {
   //initialising IClass1Obj
   //some code
   //Set Interface objet back to C++
   IClass1.GetClass2InterfacePtr(this);
   //call SayHellow, which inturn will call CallMe() on this
   IClass1.SayHellow();

  }
  void CallMe()
  {
    MessageBox.Show("Hurray I got a call!!");
  }
}

第5步：

我的代码编译正常，运行正常，执行正常，没有异常报告

Step 5:
I code is compiling fine, running fine, executing fine, No exception reported

But the problem is I can't say "Hurray I got a call!!" :( 

提前致谢

Thanks in advance

推荐答案

如果你只想设置一个回调函数，那就很容易了，如我的文章中所述。



文章如何制作C ++类。

If you only what to set a callback function it is fairly easy, as described in my article.

A more complex scenario with classes is in the article How to Marshal a C++ Class displayed.

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