return true from IsBeingDeleted() if any of the parent windows is marked for destruction too (see #9867)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@55570 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -385,6 +385,8 @@ All (GUI):
 - Show busy cursor in wxLaunchDefaultBrowser and add wxBROWSER_NOBUSYCURSOR.
 - Added wxFlexGridSizer::Is{Row,Col}Growable() (Marcin Wojdyr).
 - Added "enabled" and "hidden" attributes to radio box items in XRC.
+- wxWindow::IsBeingDeleted() now returns true not only if the window itself is
+  marked for destruction but also if any of its parent windows are.
 
 wxGTK:
 

include/wx/window.h

@@ -199,7 +199,7 @@ public:
     bool DestroyChildren();
 
         // is the window being deleted?
-    bool IsBeingDeleted() const { return m_isBeingDeleted; }
+    bool IsBeingDeleted() const;
 
     // window attributes
     // -----------------

interface/wx/window.h

@@ -439,6 +439,20 @@ public:
     */
     virtual void DestroyChildren();
 
+    /**
+        Returns true if this window is in process of being destroyed.
+
+        The top level windows are not deleted immediately but are rather
+        scheduled for later destruction to give them time to process any
+        pending messages, see Destroy() description.
+
+        This function returns @true if this window, or one of its parent
+        windows, is scheduled for destruction and can be useful to avoid
+        manipulating it as it's usually useless to do something with a window
+        which is on the point of disappearing anyhow.
+     */
+    bool IsBeingDeleted() const;
+
     /**
         Disables the window. Same as @ref Enable() Enable(@false).
 

src/common/wincmn.cpp

@@ -379,6 +379,12 @@ wxWindowBase::~wxWindowBase()
 #endif
 }
 
+bool wxWindowBase::IsBeingDeleted() const
+{
+    return m_isBeingDeleted ||
+            (!IsTopLevel() && m_parent && m_parent->IsBeingDeleted());
+}
+
 void wxWindowBase::SendDestroyEvent()
 {
     wxWindowDestroyEvent event;