Problem with Painting logic

[narayanagvs]

Hi, In my application I have a window in which there are few buttons below the window and on clicking each of the buttons Activex controls from a list with certain conditions are shown in the same window above these buttons .This is done using painting logic.The Problem I am having here is there are prev screen left overs when I swiitch between button clicks. This bug appears only once when I open the window and do the button clicks.If at all I Minimize and Maximize my window atleast once this bug doesn't appear and every works fine. I face the issue only when I use DeviceindependentBitmap to Bitblt.I assume the problem is with clipregions. Please suggest me on the same. Below is the snippets of code

case WM_PAINT:{
RECT rc;
HDC hdcMem, hdcOld;
HBRUSH hbrBkGnd;
HFONT hfntOld;
PAINTSTRUCT ps;
DWORD dwConnectState;

	// Don't bother Processing any WM\_PAINT messages if you are in the process of 
	// shutting down Window.
	if(! bViewClosing )	 
	{
	// Get the window update region before calling BeginPaint. 
	// Note: The BeginPaint function automatically validates the update region, so any call 
	// to GetUpdateRgn made immediately after the call to BeginPaint retrieves an empty update 

	region. 
	if(hClipRgn == NULL)
	{
		hClipRgn = CreateRectRgn(0,0,0,0);
		GetUpdateRgn(hWnd, hClipRgn, FALSE);
	}
	ws = (WIN\_STRUCTPTR) GetWindowLong( hWnd, 0 );
	BeginPaint(hWnd, (LPPAINTSTRUCT)&ps);

	// Get the size of the client rectangle.
	GetClientRect(hWnd, &rc);

	// Create a compatible DC.
	hdcMem = CreateCompatibleDC(ps.hdc);

	bool createFailed = false;

	// Create a DIBSection big enough for our client rectangle.
	long width = rc.right-rc.left;
	long height = rc.bottom-rc.top;
	//Start of CRL00107461 
	HWND dDeskWnd = GetDesktopWindow();
	HDC hdc= GetDC(dDeskWnd);
	int nBitCount = GetDeviceCaps(hdc,BITSPIXEL);
	if (hbmDIBSection == NULL || dibSectionWidth < width || dibSectionHeight < height)
	{
		if (hbmDIBSection != NULL)
			DeleteObject(hbmDIBSection);
		
		BITMAPINFO bmi = {0};
		bmi.bmiHeader.biSize        = sizeof(BITMAPINFOHEADER);
		bmi.bmiHeader.biWidth       = width;
		bmi.bmiHeader.biHeight      = height;
		bmi.bmiHeader.biPlanes      = 1;
	    bmi.bmiHeader.biBitCount    = nBitCount;//32;       // 32 bits per pixel.//CRL00107461
		bmi.bmiHeader.biCompression = BI\_RGB;
		bmi.bmiHeader.biSizeImage   = bmi.bmiHeader.biWidth \* bmi.bmiHeader.biHeight \* 4; 

// 4

[Niklas L]

You could try to call InvalidateRect[^] when switching control. It will invalidate the background and force a repaint if the bErase parameter is TRUE.

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