public override void SetObjectValue (NSTableView tableView, NSObject theObject, NSTableColumn tableColumn, int row)
			{
				NSString newNSValue = theObject as NSString;
				if (newNSValue == null)
					return;
				string newValue = newNSValue.ToString ();
				int columnIndex = tableView.FindColumn ((NSString)tableColumn.Identifier);
				BookmarkManager.Entry entry = entries[row];
				switch (columnIndex) {
				case 0:
					if (!string.IsNullOrWhiteSpace (newValue))
						entry.Name = newValue;
					break;
				case 1:
					entry.Notes = newValue;
					break;
				case 2:
					if (!string.IsNullOrWhiteSpace (newValue))
						entry.Url = newValue;
					break;
				default:
					break;
				}
				manager.CommitBookmarkChange (entry);
			}
			public override NSObject GetObjectValue (NSTableView tableView, NSTableColumn tableColumn, int row)
			{
				if (tableColumn == null)
					return null;

				int columnIndex = tableView.FindColumn ((NSString)tableColumn.Identifier);
				switch (columnIndex) {
				case 0:
					return new NSString (entries[row].Name);
				case 1:
					return new NSString (entries[row].Notes);
				case 2:
					return new NSString (entries[row].Url);
				default:
					return null;
				}
			}