Avoid crashes in wxGenericListCtrl client<->screen conversion code.

At least in wxUniv build, DoScreenToClient() can be called before the main
control window is created which results in a crash when attempting to forward
to its DoScreenToClient() version.

Check for m_mainWin being non-NULL before using it to at least avoid the
crash, even if it's not really clear whether this is a 100% correct fix.

Closes #12390.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65831 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/generic/listctrl.cpp b/src/generic/listctrl.cpp
index 1a82b85138d5ac8c335dc62d5279eaaeed2078e3..5a3ef5ac9064b6e9085e8ad26429a09dc9f8d89f 100644 (file)
--- a/src/generic/listctrl.cpp
+++ b/src/generic/listctrl.cpp
@@ -5061,12 +5061,22 @@ bool wxGenericListCtrl::DoPopupMenu( wxMenu *menu, int x, int y )
 
 void wxGenericListCtrl::DoClientToScreen( int *x, int *y ) const
 {
-    m_mainWin->DoClientToScreen(x, y);
+    // It's not clear whether this can be called before m_mainWin is created
+    // but it seems better to be on the safe side and check.
+    if ( m_mainWin )
+        m_mainWin->DoClientToScreen(x, y);
+    else
+        wxControl::DoClientToScreen(x, y);
 }
 
 void wxGenericListCtrl::DoScreenToClient( int *x, int *y ) const
 {
-    m_mainWin->DoScreenToClient(x, y);
+    // At least in wxGTK/Univ build this method can be called before m_mainWin
+    // is created so avoid crashes in this case.
+    if ( m_mainWin )
+        m_mainWin->DoScreenToClient(x, y);
+    else
+        wxControl::DoScreenToClient(x, y);
 }
 
 void wxGenericListCtrl::SetFocus()