Using Call Back Function C# delegate dll in C++
but i have a error how can't i fix it?
this is my c# Code
public delegate void Callback_Calc(int nResult); [Guid("180726E3-7185-4224-BF27-3A7A60E5D1A7")] public interface ICal { int Add(int a, int b); void Add_Callback(int a,int b,IntPtr Callback_Result); } [Guid("9FF07EDD-8DEE-4CCA-9BDF-2C753F7717AC")] public class Calc : ICal { public int Add(int a, int b) { return (a + b); } public void Add_Callback(int a, int b, IntPtr Callback_Result) { int sum = a + b; Callback_Calc func = (Callback_Calc)Marshal.GetDelegateForFunctionPointer(Callback_Result, typeof(Callback_Calc)); func(sum); } } this is my C++ Code
extern "C" void __stdcall callback_func(int nResult); void __fastcall TForm2::btn2Click(TObject *Sender) { ICal *m_Calc; HRESULT hr = CoInitialize(NULL); hr = CoCreateInstance(CLSID_Calc,NULL,CLSCTX_INPROC_SERVER,IID_ICal,reinterpret_cast<void**>(&m_Calc)); if(FAILED(hr)) { CoInitialize(NULL); } int a = m_Calc->Add(2,5); lbl1->Caption = a; m_Calc->Add_Callback(10,10,(_Callback_Calc *)callback_func); CoInitialize(); } extern "C" void __stdcall callback_func(int nResult) { int a = nResult; int b = nResult; }this is my C++ error Code
[C++ Error] ComputAddTest.cpp(55): E2034 Cannot convert '_Callback_Calc *' to 'long' [C++ Error] ComputAddTest.cpp(55): E2342 Type mismatch in parameter 'Callback_Result' (wanted 'long', got '_Callback_Calc *') [C++ Error] ComputAddTest.cpp(56): E2193 Too few parameters in call to '__stdcall CoInitialize(void *)'
thank you
