Flickering while painting on the client area

See more:

C++

C

Win32

GDI

I have created a simple Win32 program which paints rectangles stored in a linked list. In the WM_PAINT message the program paints all the nodes (rectangles) in the linked list in a loop. The problem is that the program flickers a bit. I found the program is annoying to use. I am using double buffering now, but it has less results that i expected. Here's my code :

case WM_PAINT:
 
    // Get DC for window
    hdc = BeginPaint(hwnd, &ps);
 
    // Create an off-screen DC for double-buffering
    hdcMem = CreateCompatibleDC(hdc);
    hbmMem = CreateCompatibleBitmap(hdc, win_width, win_height);
 
    hOld   = SelectObject(hdcMem, hbmMem);
 
    // Draw into hdcMem here
	while(/*Linked list*/)
	{
		Rectangle(/*...*/);
		//.... other lines of code
	}
 
    // Transfer the off-screen DC to the screen
    BitBlt(hdc, 0, 0, win_width, win_height, hdcMem, 0, 0, SRCCOPY);
 
    // Free-up the off-screen DC
    SelectObject(hdcMem, hOld);
    DeleteObject(hbmMem);
    DeleteDC    (hdcMem);
 
    EndPaint(hwnd, &ps);
    return 0;

What's wrong with the above code ? Is there a better way to do paintings like this using GDI ?