C++ struct to C# With Delegate

[Gezan]

I have a question. The struct below is used to handle the callback of a Unmannaged c++ dll.

      struct CALLBACK
      {
          typedef BOOL (*CALL_AP) (LPVOID pThis, GT_HANDLE hFrom, GT_ERROR Error, GT_CALLBACK_TYPE dwType, LPVOID pData);
          BOOL IsVaild()  {
              return (m_pCall != NULL);.
          }
          LPVOID        m_pThis;
          CALL_AP    m_pCall;
      };
 

I tried to translate this struct but probabaly the problem will lie here in the tranalsation of the struct.

      [StructLayout(LayoutKind.Sequential)]
          struct CALLBACK
          {
              public delegate bool CALL_AP(IntPtr pThis, UInt32 hFrom, GT_STATUS Status, GT_CALLBACK_TYPE dwType, IntPtr pData);
              public bool IsVaild()
              {
                  return m_pCall != null;
              }
              public IntPtr m_pThis;
              public CALL_AP m_pCall;
          }
 

but if i use this code the callback function will run 1 time and crash with a unhandled win32 exception

[Banfa]

By translate you mean you copy the function pointer returned by the DLL to the delegate?

I am reasonably sure that you just can't do that. You need to return to the C# application a .NET class or a C++/CLR defined delegate that can then make the call to the native function.

That is the native/managed interface has to remain in the C++ code, the C# must only have visibility of managed classes and functions.

[Gezan]

thnx for the quick reply. Yes by translate i meant just copy and translate the structure.

I am kind of new to C# . Can u give me an example of how i need to to post this structure to the dll. And let the delegate inside the structure handle the callback ?