Creating two Windows/Forms

Hello,

I am trying to create an application which will display two forms, one will "roll" a dice (create a random number) and I will then pass this to the other window/form which will display the result.

Unfortunately I need to be able to do it within another thread so I will be sharing memory between them so I can pass the data across.

So far i've completed the first screen, added menus and the random number side of things and now i'm trying to implement a second form in a similar attempt as the first one to display the results. I'm adding the CreateWindowEx() command in the WM_CREATE section so it is created when the first window starts.

I've been trawling the internet and documents for a few days and I still can't find a solution to what I need.

I've posted the entire solution I have so far (Minus the random number stuff, not really important).

Would anybody be able to help in getting another window up and running? Im primarily from a C# background and i've not used C for long so it's all a bit new to me still.

Thank you for your time.


The application so far

Code:

//////////////////
// WINDOWS MAIN //
//////////////////
int WINAPI WinMain(HINSTANCE hThisInst, HINSTANCE hPrevInst, 
				   LPSTR lpszArgs, int nWinMode)
{
	// Declaration of window class (used to register program), 
	// handle to window (returned by CreateWindow)
	// and windows message (holds messages received from windows)
	WNDCLASS wcl;
	HWND hwnd;
	MSG msg;

	// Name of window and window class
	LPCWSTR szWinName   = L"DiceRoller - Producer";
	LPCWSTR szClassName = L"DiceRollProd";

	// Set up the windows class struct
	wcl.hInstance = hThisInst;
	wcl.lpszClassName = szClassName;
	wcl.lpfnWndProc = WindowFunc;
	wcl.style = 0;
	wcl.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wcl.hCursor = LoadCursor(NULL, IDC_ARROW);
	wcl.lpszMenuName = NULL;
	wcl.cbClsExtra = 0;
	wcl.cbWndExtra = 0;
	wcl.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);

	// Register the windows class
	if(!RegisterClass(&wcl))
	{
		return 0;
	}

	// Create the main window
	hwnd = CreateWindowEx(0,
		szClassName,
		szWinName,
		WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_CLIPCHILDREN,
		100,
		100,
		400,
		400,
		HWND_DESKTOP,
		NULL,
		hThisInst,
		NULL );


	// Show the main window
	ShowWindow(hwnd, nWinMode);
	UpdateWindow(hwnd);

	// Main message processing loop
	while(GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return (int)msg.wParam;
}



//////////////////////
// WINDOWS FUNCTION //
//////////////////////
LRESULT CALLBACK WindowFunc(HWND hMainWindow, UINT message, 
							WPARAM wParam, LPARAM lParam)
{
	//Fields
	WCHAR buffer[256];
	struct DiceData storage;
	HWND hwnd;

	// Act on current message
	switch(message)    
	{
	case WM_CREATE:
		AddMenus(hMainWindow);

		hwnd = CreateWindowEx(
			0,
			"ChildWClass",
			(LPCTSTR) NULL,
			WS_CHILD | WS_BORDER | WS_VISIBLE,
			0,
			0,
			400,
			400,
			hMainWindow,
			NULL,
			NULL,
			NULL);

		ShowWindow(hwnd, SW_SHOW);
		UpdateWindow(hwnd);

		break;

In the second call to CreateWindowEx, you are saying that you want a child window but you aren't specifying required parameters.

CreateWindowEx Function (Windows)

You still need to specifiy the HINSTANCE and a child window identifier (just a unique integer value). To get the HINSTANCE when you aren't in WinMain (without declaring a global variable), look into GetWindowLong ( GetWindowLong Function (Windows) ).

Oh, and make sure that "ChildWClass" is actually a class. Note that classes aren't global unless specifically set like that, so you can't register a class from another application unless the application has specified CS_GLOBALCLASS when it registered the class.

Another thing, when GetMessage encounters an error, it returns -1. So you shouldn't check to see whether it's true, check to see if it is greater than 0 instead.

Excellent, thank you for the help.