SharpTreeView: change SelectedNode/ActiveNodes from List to HashSet (fixes performance issue when selecting lots of nodes)

SharpTreeView/SharpTreeNode.cs

@@ -20,13 +20,13 @@ namespace ICSharpCode.TreeView
 
 		static SharpTreeNode()
 		{
-			SelectedNodes = new List<SharpTreeNode>();
-			ActiveNodes = new List<SharpTreeNode>();
+			SelectedNodes = new HashSet<SharpTreeNode>();
+			ActiveNodes = new HashSet<SharpTreeNode>();
 			StartCuttedDataWatcher();
 		}
 
-		public static List<SharpTreeNode> SelectedNodes { get; private set; }
-		public static List<SharpTreeNode> ActiveNodes { get; private set; }
+		public static HashSet<SharpTreeNode> SelectedNodes { get; private set; }
+		public static HashSet<SharpTreeNode> ActiveNodes { get; private set; }
 
 		static SharpTreeNode[] ActiveNodesArray
 		{

SharpTreeView/SharpTreeView.cs

@@ -166,7 +166,7 @@ namespace ICSharpCode.TreeView
 				SharpTreeNode.SelectedNodes.Remove(node);
 			}
 			foreach (SharpTreeNode node in e.AddedItems) {
-				SharpTreeNode.SelectedNodes.AddOnce(node);
+				SharpTreeNode.SelectedNodes.Add(node);
 			}
 
 			if (IsKeyboardFocusWithin) {
@@ -174,9 +174,8 @@ namespace ICSharpCode.TreeView
 					SharpTreeNode.ActiveNodes.Remove(node);
 				}
 				foreach (SharpTreeNode node in e.AddedItems) {
-					SharpTreeNode.ActiveNodes.AddOnce(node);
+					SharpTreeNode.ActiveNodes.Add(node);
 				}
-				SortActiveNodes();
 			}
 			base.OnSelectionChanged(e);
 		}
@@ -184,9 +183,8 @@ namespace ICSharpCode.TreeView
 		protected override void OnPreviewGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
 		{
 			foreach (SharpTreeNode node in SelectedItems) {
-				SharpTreeNode.ActiveNodes.AddOnce(node);
+				SharpTreeNode.ActiveNodes.Add(node);
 			}
-			SortActiveNodes();
 		}
 
 		protected override void OnPreviewLostKeyboardFocus(KeyboardFocusChangedEventArgs e)
@@ -195,15 +193,6 @@ namespace ICSharpCode.TreeView
 				SharpTreeNode.ActiveNodes.Remove(node);
 			}
 		}
-
-		void SortActiveNodes()
-		{
-			SharpTreeNode.ActiveNodes.Sort(delegate(SharpTreeNode n1, SharpTreeNode n2) {
-				var index1 = Items.IndexOf(n1);
-				var index2 = Items.IndexOf(n2);
-				return index1.CompareTo(index2);
-			});
-		}
 		
 		#endregion