Display Update Speed for Dialog Boxes


Desktop-as-a-Service Designed for Any Cloud ? Nutanix Frame

Environment: Visual C++ 6

I've been searching for a simple answer to a problem. I wanted to increase the display update rate for a dialog box. This (modeless) dialog includes a progress bar, and it displays a percentage number and another number indicating progress (initially in edit boxes). When I'd disable the display update functions (m_progress.SetPos() and dlg->UpdateData(FALSE), the function generating these numbers would complete in half the time. I tried using a DC and the TextOut() function (rather than updating the edit boxes), but that didn't speed things up either. Until I looked at the myriad of windows messages sent when I used UpdateData(FALSE) I didn't realize the origin of the wasted time. It's all due to the "repainting" of the main app window (frame). Since I'm (relatively) inexperienced with MFC, I'm delighted to find such a simple solution. When you display the dialog box hide the main window (if you don't require it's use at that time). I don't use the UpdateData(FALSE) function, but I still see the information on the screen, and the progress bar updates as expected (in a negligible amount of time). I'm sure some of you may see holes in my theory, but this works fine for my app.

BOOL CMyDialog::OnInitDialog()

 CWnd* temp_main_wnd = AfxGetMainWnd();


void CMyOperation::GetDataAndDisplay()
 unsigned int  m_percent = 0;
 unsigned int  m_other_data = 0;

 int x = 200;
 int y = 200;

 CMyDialog* dlg;

 CDC* TempDC = NULL;
 CDC  LocalDC;

 dlg = new CMyDialog;
 dlg->Create(IDD_MY_DIALOG, NULL);

 TempDC = dlg->GetDC();

 LocalDC.m_hAttribDC = TempDC->m_hAttribDC;
 LocalDC.m_hDC = TempDC->m_hDC;


 // When it's time to update the display...


 LocalDC.TextOut(x, y, m_percent);
 LocalDC.TextOut(x, y + 50, m_other_data);


void CMyDialog::OnCancel()
 CWnd* temp_main_wnd = AfxGetMainWnd();



This article was originally published on January 14th, 2000

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date