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CCmdTarget::BeginWaitCursor

Call this function to display the cursor as an hourglass when you expect a command to take a noticeable time interval to execute.

void BeginWaitCursor( );

The framework calls this function to show the user that it is busy, such as when a CDocument object loads or saves itself to a file.

The actions of BeginWaitCursor are not always effective outside of a single message handler as other actions, such as OnSetCursor handling, could change the cursor.

Call EndWaitCursor to restore the previous cursor.

// The following example illustrates the most common case 
// of displaying the hourglass cursor during some lengthy 
// processing of a command handler implemented in some 
// CCmdTarget-derived class, such as a document or view. 
void CMyView::OnBeginSleepEnd()
{
   BeginWaitCursor(); // display the hourglass cursor 
   // do some lengthy processing
   Sleep(3000);
   EndWaitCursor(); // remove the hourglass cursor
}

// The next example illustrates RestoreWaitCursor. 
void CMyView::OnBeginDlgRestore()
{
   BeginWaitCursor(); // display the hourglass cursor 
   // do some lengthy processing 
   // The dialog box will normally change the cursor to 
   // the standard arrow cursor, and leave the cursor in 
   // as the standard arrow cursor when the dialog box is 
   // closed.
   CFileDialog dlg(TRUE);
   dlg.DoModal();

   // It is necessary to call RestoreWaitCursor here in order 
   // to change the cursor back to the hourglass cursor.
   RestoreWaitCursor();
   // do some more lengthy processing
   Sleep(3000);
   EndWaitCursor(); // remove the hourglass cursor
}

// In the above example, the dialog was clearly invoked between 
// the pair of calls to BeginWaitCursor and EndWaitCursor. 
// Sometimes it may not be clear whether the dialog is invoked  
// in between a pair of calls to BeginWaitCursor and EndWaitCursor. 
// It is permissable to call RestoreWaitCursor, even if  
// BeginWaitCursor was not previously called.  This case is  
// illustrated below, where CMyView::AnotherFunction does not 
// need to know whether it was called in the context of an 
// hourglass cursor. 
void CMyView::OnDlgRestore()
{
   // some processing ...
   CFileDialog dlg(TRUE);
   dlg.DoModal();
   RestoreWaitCursor();

   // some more processing ...
}

// If the dialog is invoked from a member function of 
// some non-CCmdTarget, then you can call CWinApp::DoWaitCursor 
// with a 0 parameter value to restore the hourglass cursor. 
void CMyObject::OnDlgDoWait()
{
   CFileDialog dlg(TRUE);
   dlg.DoModal();
   AfxGetApp()->DoWaitCursor(0); // same as CCmdTarget::RestoreWaitCursor   
}

Header: afxwin.h

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