Problem with WM_KEYDOWN

It isnt working for me for some reason..
When i press a key, all it does is Deactivate the window, can someone please try to help:

Code:

---

        case WM_KEYDOWN:
                {
                        switch((int)wParam)
                        {
                        case VK_LEFT:
                                MessageBox(NULL, "Left Button Pressed", "KEYPRESS", MB_OK);
                                break;

                        case VK_RIGHT:
                                MessageBox(NULL, "Right Button Pressed", "KEYPRESS", MB_OK);
                                break;

                        case VK_UP:
                                MessageBox(NULL, "Up Button Pressed", "KEYPRESS", MB_OK);
                                break;

                        case VK_DOWN:
                                MessageBox(NULL, "Down Button Pressed", "KEYPRESS", MB_OK);
                                break;
                        }
                }
                break;

---

Thanks to all who try to help

Try changing the switch statement to:

switch(LOWORD(wParam))

Ok, that LOWORD(wParam) worked, but only after i took out my WM_PAINT message, here it is:

Code:

---

        case WM_PAINT:
                {
                        HDC Window = GetDC(hwnd);
                        HDC mem = CreateCompatibleDC(Window);

                       

                        BitBlt(Window, 0, 0, 384, 288, mem, 0, 0, BLACKNESS);
                        BitBlt(Window, 394, 0, 246, 288, mem, 0, 0, BLACKNESS);
                        BitBlt(Window, 0, 298, 640, 177, mem, 0, 0, BLACKNESS);

                        DeleteDC(mem);
                }
                break;
                */

---

Is something wrong with that?

In other words, you are not merely casting a WPARAM variable ( no doubt a typedef for a long int) to an int. Rather you are extracting the "lower" half of it...

Yes! You must CreateCompatibleBitmap a HBITMAP variable, making it compatible to "Window". Then SelectObject(mem, bitmap).

Really, though, you should call BeginPaint() and EndPaint() in the WM_PAINT handler, too.

Quote:

---

Originally posted by Sebastiani
Really, though, you should call BeginPaint() and EndPaint() in the WM_PAINT handler, too.

---

That's very true....Using GetDC will not remove the WM_PAINT Message from the message queue.........

WM_PAINT is called because a region has been 'invalidated'. BeginPaint() validates this region. GetUpdateRegion() can be called to find it prior to this.

This is EVIL!

Code:

---

HDC Window = GetDC(hwnd);
HDC mem = CreateCompatibleDC(Window);
BitBlt(Window, 0, 298, 640, 177, mem, 0, 0, BLACKNESS);

DeleteDC(mem);

---

This is a mem leak. At no point is the HDC 'Window' released with a call to ReleaseDC(). Be very careful about Creating / Getting GDI resources. They not only must be freed but put back EXACTLY the way you found them.

Better to use the DC in the paint struct or the return from BeginPaint().

If you create a BMP ensure you catch the one in the DC and replace it before deleting them both (the DC and the BMP).