CCmdTarget::BeginWaitCursor

Article
06/10/2015

Appelez cette fonction pour afficher le curseur sablier comme lorsque vous attendez une commande de prendre un intervalle de temps apparent pour exécuter.

void BeginWaitCursor( );

Notes

L'infrastructure appelle cette fonction pour afficher l'utilisateur qu'elle est occupée, par exemple lorsqu'un objet de CDocument charge ou s'enregistre dans un fichier.

Les actions d' BeginWaitCursor ne sont pas toujours le plus efficace d'un gestionnaire de messages unique que d'autres actions, par exemple OnSetCursor gestion, peuvent modifier le curseur.

Appel EndWaitCursor pour restaurer le curseur précédent.

Exemple

// 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   
}