HDC OnPaint事件的问题

Question

//以下代码执行后没有任何效果，是MFC DIALOG程序，请各位看看是什么问题
void MyDialog::OnPaint() 
{
PAINTSTRUCT ps;
HDC hDC;
struct GdiList *pNode;
int iX1,iX2,iY1,iY2;
// Start the Painting of the Screen
hDC = ::BeginPaint(this->m_hWnd,&ps);
// Draw the Full Bitmap
if (fDIBitmap)
{
// Get the Client Rectangle
GetClientRect(&m_Rect);
if (!fConnected)
{
m_hMemDC = CreateCompatibleDC(hDC);
m_hDDBitmap = CreateCompatibleBitmap(hDC,iScreenWidth,iScreenHeight);
SelectObject(m_hMemDC,m_hDDBitmap);
}
BitBlt(hDC,0,0,iScreenWidth,iScreenHeight,m_hMemDC,iHScrollPos,-iVScrollPos,SRCCOPY);
    if (!fConnected)
{
// Delete the Bitmap
DeleteObject(m_hDDBitmap);
// Delete the Mem DC
DeleteDC(m_hMemDC);
}
}
// End the Painting of the Screen
EndPaint(&ps);
}

Answer 1

Debug跟踪一下就会知道问题出在哪了。大部分显示不出都是位图错误引起的。