[Mono-dev] ListBox.cs ownder draw variable size

[jkeymer]

Handles calculation if the listbox scroll area of variable high, owner 
draw boxes,

Index: Managed.Windows.Forms/System.Windows.Forms/ListBox.cs
===================================================================
--- Managed.Windows.Forms/System.Windows.Forms/ListBox.cs    (Revision 
103872)
+++ Managed.Windows.Forms/System.Windows.Forms/ListBox.cs    (Arbeitskopie)
@@ -2145,9 +2145,20 @@
             last_visible_index = LastVisibleItem ();
 
             int diff = top_item - top_index;
-
+            int delta = ItemHeight * diff;
+            if (DrawMode == DrawMode.OwnerDrawVariable) {
+                delta = 0;
+                if ( top_index < top_item ) {
+                    for ( int i = top_index; i < top_item; i++ )
+                        delta += GetItemHeight(i);
+                }
+                else {
+                    for ( int i = top_item; i < top_index; i++ )
+                        delta -= GetItemHeight(i);
+                }
+            }
             if (IsHandleCreated)
-                XplatUI.ScrollWindow (Handle, items_area, 0, ItemHeight 
* diff, false);
+                XplatUI.ScrollWindow (Handle, items_area, 0, delta, false);
         }
 
         #endregion Private Methods