Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Ending DoModal loop when owner window is destroyed

Posted on 1997-12-08
3
Medium Priority
?
1,085 Views
Last Modified: 2013-11-20
I need to close a whole "stack" of windows when a stimulus occurs at the top level. The Windows Owner/Owned relationship will destroy an owned window when the owner is destroyed, but this will not cause EndDialog to run (or, more importantly, EndModalLoop). So, after the window is destroyed, the app is still (at some level of the call stack), running in RunModalLoop and when the app returns there, the call to ContinueModal still returns TRUE (because EndModalLoop has yet to run).

I need to fix this for a number of cases in the application, and it would be cumbersome to add a special handler (say, OnDestroy) to every class or to interpose a special MyAppCDialog class with this handler in the class hierarchy.

What can I do to get EndDialog or EndModalLoop to run?
0
Comment
Question by:postrowski
  • 2
3 Comments
 
LVL 10

Accepted Solution

by:
RONSLOW earned 400 total points
ID: 1311822
Loop thru all your child windows (and children of children)

Get a pointer to the CWnd* (derived) object for each one

Check if the pointer IsKindOf CDialog.

If so, call EndDialog for the window.

0
 

Author Comment

by:postrowski
ID: 1311823
Well, I can't loop through all of the child windows, since an owned window is not a child window, but the IsKindOf function helped out a lot.

What I can do is enumerate all of the top level windows in the system with:

EnumWindows(CMyApp::CloseIfOwned, (LPARAM)MAIN->m_hWnd);

And then check each top level window to see if it is owned by the main application window (or owned by a window that is owned by the main window, etc.). If so, check to see if it IsKindOf(CDialog) or IsKindOf(CPropertySheet) (since CPropertySheet is not descended from CDialog). This approach seems to work just fine. The enumeration callback function is listed below. Thanks for your help.

BOOL CALLBACK CMyApp::CloseIfOwned(
HWND hwnd,// handle to window in question
LPARAM lParam // handle to main app window
)
{
   HWND hOwner;
   HWND hTmp = hwnd;
   do
   {
      hOwner = ::GetWindow(hTmp, GW_OWNER);

      if(hOwner == NULL)
         return TRUE; // always continue enumeration.

      hTmp = hOwner;
   } while (hOwner != (HWND)lParam);

   // Here we know that hwnd is owned by us.

   CWnd *pWnd;
   pWnd = CWnd::FromHandlePermanent(hwnd);
   if(pWnd != NULL)
   {
      if(pWnd->IsKindOf(RUNTIME_CLASS(CDialog)) ||
         pWnd->IsKindOf(RUNTIME_CLASS(CPropertySheet)))
         ((CDialog *)pWnd)->EndDialog(IDCANCEL);
   }

   ::DestroyWindow(hwnd);

   return TRUE; // always continue enumeration.
}
0
 
LVL 10

Expert Comment

by:RONSLOW
ID: 1311824
Looks like all you needs was a push in the right direction.

Glad to have helped

0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

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

Introduction: Load and Save to file, Document-View interaction inside the SDI. Continuing from the second article about sudoku.   Open the project in visual studio. From the class view select CSudokuDoc and double click to open the header …
Introduction: The undo support, implementing a stack. Continuing from the eigth article about sudoku.   We need a mechanism to keep track of the digits entered so as to implement an undo mechanism.  This should be a ‘Last In First Out’ collec…
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.
Look below the covers at a subform control , and the form that is inside it. Explore properties and see how easy it is to aggregate, get statistics, and synchronize results for your data. A Microsoft Access subform is used to show relevant calcul…
Suggested Courses

885 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