Fix wxWindowModalDialogEvent::GetReturnCode() on Windows.

*Lots* of native dialogs don't call SetReturnCode() in their ShowModal()
implementations in wxMSW. Rather than fixing them all - and having them
accidentally broken again and again in the future - fix this just in the
generic ShowWindowModal() implementation. This may not be the most elegant fix,
but it is bullet-proof.

Also revert previous attempt to fix just wxMessageDialog in r74776.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75089 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/dlgcmn.cpp

@@ -517,7 +517,13 @@ IMPLEMENT_DYNAMIC_CLASS(wxWindowModalDialogEvent, wxCommandEvent)
 
 void wxDialogBase::ShowWindowModal ()
 {
-    ShowModal();
+    int retval = ShowModal();
+    // wxWindowModalDialogEvent relies on GetReturnCode() returning correct
+    // code. Rather than doing it manually in all ShowModal() overrides for
+    // native dialogs (and getting accidentally broken again), set it here.
+    // The worst that can happen is that it will be set twice to the same
+    // value.
+    SetReturnCode(retval);
     SendWindowModalDialogEvent ( wxEVT_WINDOW_MODAL_DIALOG_CLOSED  );
 }
 

src/msw/msgdlg.cpp

@@ -586,9 +586,7 @@ int wxMessageDialog::ShowMessageBox()
     // do show the dialog
     int msAns = MessageBox(hWnd, message.t_str(), m_caption.t_str(), msStyle);
 
-    int ret = MSWTranslateReturnCode(msAns);
-    SetReturnCode(ret);
-    return ret;
+    return MSWTranslateReturnCode(msAns);
 }
 
 int wxMessageDialog::ShowModal()
@@ -623,9 +621,7 @@ int wxMessageDialog::ShowModal()
             msAns = IDOK;
         }
 
-        int ret = MSWTranslateReturnCode(msAns);
-        SetReturnCode(ret);
-        return ret;
+        return MSWTranslateReturnCode( msAns );
     }
 #endif // wxHAS_MSW_TASKDIALOG