AppDocObserverDelegate appDocumentCreating appDocumentIsBeingDestructed delegateName documentRestore documentSave getGuiDocDelegateName IDocument m_pDoc setDocument ~AppDocObserverDelegate

appDocumentIsBeingDestructed() virtual void appDocumentIsBeingDestructed ( ) virtual 应用文档即将析构时回调 在 App::IDocument 析构前触发，可执行资源清理或提示。