this code is not working

I am trying to take a screenshot of my desktop (as you do with the printscreen button) but it is not working
I am trying to copy each pixel from the desktop onto a memory DC and then copy the bitmap from memory DC onto my window.
Here is the code:

Code:

---

PAINTSTRUCT ps, ps1;
        int x, y;
        HDC parenthdc, winhdc;
        HWND parenthwnd;
        HDC  memhdc;
        HBITMAP hbmp;
        BITMAP bm;

        //Create the bitmap
        winhdc = GetDC(hwnd);
        memhdc = CreateCompatibleDC(winhdc);
        hbmp = CreateCompatibleBitmap(memhdc, 1000,1000);
        ReleaseDC(hwnd, winhdc);

  switch(Message)
  {
 
  case WM_PAINT:
          parenthwnd = GetParent(hwnd);
          parenthdc = BeginPaint(parenthwnd, &ps);
          //-----------------------
          for(x=0;x<1000;x++)
          {
                  for(y=0;y<1000;y++)
                  {
                          SetPixel(memhdc, x,y,GetPixel(parenthdc, x,y));
                  }
          }
          winhdc = BeginPaint(hwnd, &ps1);
          BitBlt(winhdc, 0,0,1000,1000,memhdc,0,0,SRCCOPY);
          EndPaint(hwnd, &ps1);
          EndPaint(parenthwnd, &ps);
          return 0;

---

Do you know why it is not putting the picture of desktop or is there any other method to get a screenshot of my desktop/

Have a look in the other post.