Virtual Key Codes

[TpOreilly]

Hi, here is my windows procedure:

LRESULT CALLBACK MessageProcedure(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)

{

static int X = 250;
static int Y = 250;
HINSTANCE hInstance;
hInstance = LoadLibrary (TEXT("Application01.exe"));

switch(message)

{
case WM_CREATE:

int MessageBoxID;
MessageBoxID = MessageBox(hWnd, TEXT(" Are ya ready kids?"), TEXT("Are ya ready kids?"),
MB_ICONQUESTION | MB_YESNO);

if (MessageBoxID == IDNO)
{
PostQuitMessage(0);
}

if (MessageBoxID == IDYES)
{
UpdateWindow(hWnd);
}

return FALSE;



case WM_PAINT:

HICON hIcon;
hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));
HDC handleDeviceContext;
PAINTSTRUCT PaintSt;
handleDeviceContext = BeginPaint(hWnd, &PaintSt);
DrawIcon(handleDeviceContext, X, Y, hIcon);
EndPaint(hWnd, &PaintSt);
break;


case WM_KEYDOWN:

switch(wParam)

case VK_LEFT:
{
X -= 5;
InvalidateRect(hWnd, NULL, TRUE);
break;
}
case VK_RIGHT:
{
X += 5;
InvalidateRect(hWnd, NULL, TRUE);
break;
}

break;

case WM_DESTROY:
PostQuitMessage(0);
break;


}


return DefWindowProc (hWnd, message, wParam, lParam);

}



The X and Y variables are integers which are used here:

DrawIcon(handleDeviceContext, X, Y, hIcon);

So the X and Y are the location of the icon.

The problem I am having is that when i press the left arrow key, nothing happens, and when i press the right arrow key it DOES go right, but it also goes right when i press the up and down kep :S

[VictorN]

Did you debug your code top be sure WM_KEYDOWN is processed for both VK_LEFT and VK_RIGHT?
Besides, why do you call DefWindowProc if you want to process this message in your own procedure? From MSDN:

WM_KEYDOWN Message
...
Return Value

An application should return zero if it processes this message.

[TpOreilly]

I call it to provide default processing for any window messages that my application does not process.

[VictorN]

I call it to provide default processing for any window messages that my application does not process.

But your application does process WM_KEYDOWN message when either VK_LEFT or VK_RIGHT code was supplied!

[TpOreilly]

I think i might be confused lol...

I havnt got "return DefWindowProc (hWnd, message, wParam, lParam);" in the case of the WM_KEYDOWN message, i have "DefWindwProc" right at the very end on the windows procedure.

[VictorN]

It doesn't matter.
if you have processed this message you have to return 0. Period!

[D_Drmmr]

Hi, here is my windows procedure:

Over 60 posts and you don't know how to use code tags?

[TpOreilly]

Oh ok.

I have done what you said, but that results in my window not showing when i run the application. It doesnt show any errors either.

[VictorN]

I have done what you said, but that results in my window not showing when i run the application. It doesnt show any errors either.

What did you do? And how?

[TpOreilly]

Returned 0.

[VictorN]

Returned 0.

Where?

[TpOreilly]

Start again As I am confused, could you correct my mistakes in my original code below and re-post it please

LRESULT CALLBACK MessageProcedure(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static int X = 250;
	static int Y = 250;
	HINSTANCE hInstance;
	hInstance = LoadLibrary (TEXT("Application01.exe"));

	switch(message)
	{
		case WM_CREATE:

			int MessageBoxID;
			MessageBoxID = MessageBox(hWnd, TEXT("         Are ya ready kids?"), TEXT("Are ya ready kids?"),
            MB_ICONQUESTION | MB_YESNO);

			if (MessageBoxID == IDNO)
			{
				PostQuitMessage(0);
			}

			if (MessageBoxID == IDYES)
			{
				UpdateWindow(hWnd);
			}

			return FALSE;

			

		case WM_PAINT:
				
				HICON hIcon;
				hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));
				HDC handleDeviceContext; 
				PAINTSTRUCT PaintSt;
				handleDeviceContext = BeginPaint(hWnd, &PaintSt);
				DrawIcon(handleDeviceContext, X, Y, hIcon);
				EndPaint(hWnd, &PaintSt);
				break;
			

		case WM_KEYDOWN:

			switch(wParam)
			
				case VK_LEFT:
			{
					X -= 5;
					InvalidateRect(hWnd, NULL, TRUE);
					break;
			}
				case VK_RIGHT:
			{
					X += 5;
					InvalidateRect(hWnd, NULL, TRUE);
					break;
			}

					



		case WM_DESTROY:
            PostQuitMessage(0);
			break; 
		

		
	}


			return DefWindowProc (hWnd, message, wParam, lParam);
	
}

[VictorN]

Start again As I am confused, could you correct my mistakes in my original code below and re-post it please

LRESULT CALLBACK MessageProcedure(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static int X = 250;
	static int Y = 250;
	HINSTANCE hInstance;
	hInstance = LoadLibrary (TEXT("Application01.exe"));

	switch(message)
	{
		....
		case WM_KEYDOWN:
			switch(wParam)
				case VK_LEFT:
			{
					X -= 5;
					InvalidateRect(hWnd, NULL, TRUE);
					break;
			}
				case VK_RIGHT:
			{
					X += 5;
					InvalidateRect(hWnd, NULL, TRUE);
					break;
			}

		case WM_DESTROY:
            PostQuitMessage(0);
			break; 
	}
			return DefWindowProc (hWnd, message, wParam, lParam);
}

Does it compile?
Note also that your case WM_KEYDOWN does not have break, so after each WM_KEYDOWN this code would call PostQuitMessage(0) and app would exit. So I wonder how it could "work" at all!

[TpOreilly]

I have added the

break;

.

Before I added that it did actually compile :P

Also, i still have the same problem.

[VictorN]

I have added the

break;

.

Before I added that it did actually compile :P

Also, i still have the same problem.

Because if you have processed WM_KEYDOWN message you have to return 0, what you don't do!