Knowledge Base

PRB: Returning FALSE from OnSetActive Doesn't Set Correct Tab

Article ID: 145864

Article Last Modified on 11/21/2006

Microsoft Foundation Class Library 4.2, when used with:
- Microsoft Visual C++ 4.0 Professional Edition
- Microsoft Visual C++ 5.0 Learning Edition

This article was previously published under Q145864

SYMPTOMS

To disallow activation of a CPropertyPage, you are supposed to be able to return FALSE from OnSetActive(). This causes the next page to be activated instead of the one the user clicked. This works fine as long as there is a next page and the next page returns TRUE from OnSetActive(). If the next page is not available, the tab you clicked will be activated but the page still points to the previous one. In other words, the tab that is activated doesn't match the page. Furthermore, the OnSetActive() function is called an additional ten times.

CAUSE

Returning FALSE from OnSetActive() prompts MFC to return a -1 from PSN_SETACTIVE. The PropertySheet control doesn't handle this correctly when the next tab is not available.

RESOLUTION

In OnSetActive(), post a message of PSM_SETCURSEL to activate a different page. Then return TRUE.

Sample Code

// CPage1 is derived from CPropertyPage
BOOL CPage1::OnSetActive()
{
   // always activate the first page instead
   GetParent()->PostMessage (PSM_SETCURSEL, 0);
   return CPropertyPage::OnSetActive();
}

/* Compile options needed: default
*/

STATUS

This behavior is by design.

Additional query words: 4.00 CPropertySheet CPropertyPage PSN_SETACTIVE OnSetActive FALSE

Keywords: kbcode kbprb kbpropsheet kbuidesign KB145864