win32 c++ dll code:
Code:
#include <windows.h>
HINSTANCE ghModule = 0;          //module handle
HWND       ghwnd ; 
BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
		ghModule = (HINSTANCE) hModule;
	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
	case DLL_PROCESS_DETACH:
		break;
	}
    return TRUE;
}

CDLLClass::CDLLClass()
{
	return;
}

CDLL BOOL SendToApp(int ID, int i)   /* this by itself did not work for me*/
{ 
	ghwnd = (HWND) ghModule;
     SendMessage(ghwnd,     // handle of destination window
                    ID,     // message to send 
                    i,     // first message parameter
                    0 );     // second message parameter

     return true;
}

int SetHook(int idHook, HOOKPROC lpfn)
{
	if (idHook == WH_GETMESSAGE)
	{
		if(gHGHook != NULL)
		{
			return -1;
		}
		
		gHGHook = SetWindowsHookEx(WH_GETMESSAGE, lpfn, gInstance, 0);
	}
	
	return 0;
}

int UnHook(int idHook)
{
	if (idHook == WH_GETMESSAGE)
	{
		if(gHGHook == NULL)
		{
			return -1;
		}
		UnhookWindowsHookEx(gHGHook);
		gHGHook = NULL;
	}
	
	return 0;
}

int CallNextHook(int idHook,
				 int nCode,
				 WPARAM wParam,
				 LPARAM lParam)
{
	if (idHook == WH_GETMESSAGE)
	{
		if(gHGHook == NULL)
		{
			return -1;
		}
		CallNextHookEx(gHGHook, nCode, wParam, lParam);
	}
	
	return 0;
}

int StartHook(HWND hApp, HWND hExcel, const CString &str)
{
	gApp = hApp;
	gExcel = hExcel;
	SetHook(WH_GETMESSAGE, GetMsgProc);
	return 0;
}

int StopHook()
{
	UnHook(WH_GETMESSAGE);
	return 0;
}
this is part of my code for dialogapp.cpp:

Code:
#define WM_U_Ctrl WM_APP + 0x100
//imported it: BOOL SendToApp(int ID, int i);

void CappDlg::OnBnClickedButton1()
{
	SendToApp(WM_U_Ctrl, 1);
	//SendMessage(WM_U_Ctrl, 5, 0);
}

LRESULT CappDlg::OnUpFromDll(WPARAM wParam, LPARAM lParam)
{
	SetDlgItemInt(IDC_EDIT1,wParam,lParam);
	return 0;
}
I was wondered how to send update field message from win32 dll to dialog app.