Michael Dutton Michael Dutton - 1 year ago 111
C++ Question

LoadBitmap fails after multiple calls

In this function, after about 90 calls (it's called in a loop and the idea is to load in a separate image each time, but I have kept it to one image for simplicity).The global variables now changed to local ones.

void CDLP_Printer_ControlDlg::DisplayBMPfromSVG(CString& strDsiplayFile)
HBITMAP hbmp_temp = (HBITMAP)::LoadImage(0, strDsiplayFile, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
if (!hbmp_temp)
//hbmp_temp = ::LoadBitmap(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB_BITMAP1));
ActionList.AddString(L"Bitmap Load Failure: GetBMPromSVG");
if (!hbmp_temp)

CBitmap bmp_temp;
mProjectorWindow.m_picControl.ModifyStyle(0xF, SS_BITMAP, SWP_NOSIZE);


I hope someone can come up with an Idea whats wrong. GetLastError returns "8" which means nothing to me.

Answer Source

To use CBitmap, declare a member data as CBitmap m_bitmap Make sure to call Detach before attaching a new handle. Detach will destroy the previous handle.

Note that if you call Detach after calling SetBitmap, the picture control's bitmap is destroyed. The result is that the picture control is painted once, but it won't be repainted. For example picture control goes blank if dialog is resized.

It's the same problem if you declare a temporary CBitmap on stack and attach the bitmap handle. That bitmap handle will be destroyed and picture control can't repaint itself.

In addition, Windows XP sometimes makes duplicate bitmap which needs to be destroyed as well. SetBitmap returns a handle to previous bitmap. In Vista+ the returned bitmap is the same one which was save in m_bitmap, we already destroy that with Detach. But in XP we need to destroy this copy if it is a different handle.

void CMyDialog::foo()
    HBITMAP save = m_bitmap;
    HBITMAP hbitmap = (HBITMAP)::LoadImage(0, filename,
    if (hbitmap)

        HBITMAP oldbmp = m_picControl.SetBitmap(m_bitmap);

        //for Windows XP special case where there might be 2 copies:
        if (oldbmp && (oldbmp != save))
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