Solved

Force Window Redraw

Posted on 2003-11-07
5
4,514 Views
Last Modified: 2013-11-20
Hi,

I have a window that has a progress bar that's supposed to show progress during a long calculation. It works fine except if you place another window over it then remove it - it never receives anymore paint messages. I've tried a list of different functions including :

InvalidateWindow(), UpdateWindow(), RedrawWindow().. then SendMessage(WM_PAINT, 0, 0).

I used these in the function that updates the progress bar so everytime it moves it should redraw its window. But this never occurs and the window will just remain white. Is there any way to really force it to redraw - I thought SendMessage() would not let the program continue until that message was processed?

Thanks
0
Comment
Question by:ragin_cajun
  • 2
  • 2
5 Comments
 
LVL 48

Expert Comment

by:AlexFM
ID: 9706200
Invalidate();
UpdateWindow();

This is a way to force window redraw. When you move another window above your window, Windows invalidates your window. Possibly your window doesn't handle WM_PAINT message. Please show your code - how do you draw progress bar.
0
 
LVL 1

Author Comment

by:ragin_cajun
ID: 9707221
This is basically how my progress bar function will run, all the different methods I tried to use are below:

void CProgressDialog::UpdateProgressBar(int i)
{
    // Set progress bar
    progress_control.SetPos(i);
    i++;
   
    // try 1
    Invalidate();
    UpdateWindow();

    // try 2
    RedrawWindow(0, 0, RDW_UPDATENOW);

    // try 3
    SendMessage(WM_PAINT, 0, 0);

    // try 4 - perhaps update parent instead?    
    CWnd *pParent;
    ::InvalidateRect(pParent->GetSafeHwnd(), NULL, 1);
    ::UpdateWindow(pParent->GetSafeHwnd());

    // try 5
    ::SendMessage(h->GetSafeHwnd(), WM_PAINT, 0, 0);

    // try 6
    ::RedrawWindow(h->GetSafeHwnd(), NULL, NULL, RDW_UPDATENOW);

    // Still no results!!! Window remains unpainted after moving another window above.
}


0
 
LVL 48

Expert Comment

by:AlexFM
ID: 9707560
Read this thread, possibly this may be also your problem:

http://www.experts-exchange.com/Programming/Programming_Languages/MFC/Q_20791684.html
0
 
LVL 3

Accepted Solution

by:
freewell earned 55 total points
ID: 9711935
Inside your calculation loop, add the following codes to allow windows to process the invalidate messages.

MSG msg;
while(bLoop)
{
  // Your loop processing

  pWnd->Invalidate(TRUE);
  while(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
  {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
  }
}
0
 
LVL 1

Author Comment

by:ragin_cajun
ID: 9712315
That's what I was missing, it worked perfectly, thanks
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This is to be the first in a series of articles demonstrating the development of a complete windows based application using the MFC classes.  I’ll try to keep each article focused on one (or a couple) of the tasks that one may meet.   Introductio…
Have you tried to learn about Unicode, UTF-8, and multibyte text encoding and all the articles are just too "academic" or too technical? This article aims to make the whole topic easy for just about anyone to understand.
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Both in life and business – not all partnerships are created equal. As the demand for cloud services increases, so do the number of self-proclaimed cloud partners. Asking the right questions up front in the partnership, will enable both parties …

867 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now