MGR: Improve performance when reducing number of rows in lists (as when selecting "Show active tasks")

svn path=/trunk/boinc/; revision=20832

checkin_notes

@@ -1796,3 +1796,10 @@ David  10 Mar 2010
         time_stats.cpp
         app_control.cpp
 
+Charlie  10 Mar 2010
+    - MGR: Improve performance when reducing number of rows in lists (as  
+        when selecting "Show active tasks") by calling ClearSelections() 
+        and SetItemCount() instead of repeatedly calling DeleteItem().
+        
+    clientgui/
+        BOINCBaseView.cpp

clientgui/BOINCBaseView.cpp

@@ -298,11 +298,12 @@ void CBOINCBaseView::OnListRender(wxTimerEvent& event) {
                     m_pListPane->SetItemCount(iDocCount);
                     m_bNeedSort = true;
                } else {
-                    // We can't just call SetItemCount() here because we need to 
+                    // The virtual ListCtrl keeps a separate its list of selected rows; 
-                    // let the virtual ListCtrl adjust its list of selected rows
+                    // make sure it does not reference any rows beyond the new last row.
-                    // to remove (deselect) any beyond the new last row
+                    // We can ClearSelections() because we called SaveSelections() above.
+                    ClearSelections();
+                    m_pListPane->SetItemCount(iDocCount);
                     for (iIndex = (iCacheCount - 1); iIndex >= iDocCount; --iIndex) {
-                        m_pListPane->DeleteItem(iIndex);
                         iReturnValue = RemoveCacheElement();
                         wxASSERT(!iReturnValue);
                     }