Failing to display dialog

[kumarmpk4u]

Hi all,
I am working on an application in which a call is made to a DLL. From that dll a dialog has to be displayed. While doing so I was not able to see the dialog. Dialog is not getting displayed. When i checked the code in debug that handle of the dialog is not assigned. What might be the possible cause for this can you help me...

thanks

[WaltP]

You didn't call the function in the DLL correctly would be my guess.

[Ancient Dragon]

If the application program is a console program then you may have to have a WinMain() inside the dll and call it from the dll. For example if you have a function named foo() in the dll then foo() would call its WinMain() using HINSTANCE that it gets by calling GetModuleHandle(). You could probably name the function anything you want, I just used WinMain()

Here's an example DLL that I did for this thread. I got some of the code from other threads here at DaniWeb.

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include "mydll.h"

BOOL MakeAWindow(HINSTANCE appInstance,int show);
LRESULT CALLBACK WndProc(HWND window,UINT msg,WPARAM wParam,LPARAM lParam);
HWND MainWindow = 0;

static int*	gInstList	[7]={ 0, 0, 0, 0, 0, 0, 0 };
static int	gInstCnt=0;




int MessageLoop()
{
	MSG msg;
	ZeroMemory(&msg, sizeof(MSG));

	while (GetMessage(&msg, 0, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

return msg.wParam;
}

INT WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance, 
                   LPSTR lpCmdLine,
                   int nShowCmd)
{
	if (!MakeAWindow(hInstance, nShowCmd))
	{
		MessageBox(0, "Window Creation -- Failed", "Error", MB_OK);
		return 0;
	}

return MessageLoop();

}

BOOL MakeAWindow(HINSTANCE appInstance,int show)
{

	WNDCLASS wc;

	wc.style         = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc   = WndProc;
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = appInstance;
	wc.hIcon         = LoadIcon(0,IDI_APPLICATION);
	wc.hCursor       = LoadCursor(0,IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
	wc.lpszMenuName  = 0;
	wc.lpszClassName = "wc";

	if (!RegisterClass(&wc))
	{
		MessageBox(0, "Failed to register the window class", "Windows Sucks!", 0);
		return FALSE;
	}
	
	MainWindow = CreateWindow("wc",
                                  "Hello",
                                  WS_OVERLAPPEDWINDOW,
				  CW_USEDEFAULT,
				  CW_USEDEFAULT,
				  CW_USEDEFAULT,
				  CW_USEDEFAULT,
				  0,
				  0,
				  appInstance,
				  0);

	if(MainWindow == NULL)
	{
		MessageBox(0,"Function CreateWindow() Failed",0,0);
		return FALSE;
	}
	ShowWindow(MainWindow, show);
	UpdateWindow(MainWindow);

	return TRUE;
}

LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam)
{
    switch(msg)
    {
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

//
// This function is exported and called from application programs
//
MYDLL_API int foo()
{
    
    HINSTANCE hInst = GetModuleHandle(NULL);
    WinMain(hInst,hInst,0,SW_SHOW);
    return 0;
}

[kumarmpk4u]

Hi all,
I have just narrowed down the error part. When my code is trying to display the dialog to the DLL the error obtained is 1812(Error_Resource_Data_Not_Found). can anyone guide me how to find which resource is missing?

[Ancient Dragon]

I think the explanation in this thread will solve that problem.

[kumarmpk4u]

The problem was resolved.
new CDynLinkLibrary(DLLNAME); was not present in the DLLMAIN function which
will enable the dll’s resource file available to the application