Exemplo n.º 1
0
        /// <summary>
        /// Based on the solution proposed here:
        /// Source: http://stackoverflow.com/questions/20244916/wpf-treeview-selection-change
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void uiElement_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            // first did the user click on a tree node?
            var source = e.OriginalSource as DependencyObject;

            while (source != null && !(source is TreeViewItem))
            {
                source = VisualTreeHelper.GetParent(source);
            }

            var itemSource = source as TreeViewItem;

            if (itemSource == null)
            {
                return;
            }

            var treeView = sender as TreeView;

            if (treeView == null)
            {
                return;
            }

            bool undoSelection = TreeViewSelectionChangedBehavior.GetUndoSelection(treeView);

            if (undoSelection == false)
            {
                return;
            }

            // Cancel the attempt to select an item.
            var result = MessageBox.Show("The current document has unsaved data. Do you want to continue without saving data?", "Are you really sure?",
                                         MessageBoxButton.YesNo, MessageBoxImage.Question, MessageBoxResult.No);

            if (result == MessageBoxResult.No)
            {
                // Cancel the attempt to select a differnet item.
                e.Handled = true;
            }
            else
            {
                // Lets disable this for a moment, otherwise, we'll get into an event "recursion"
                treeView.PreviewMouseDown -= uiElement_PreviewMouseDown;

                // Select the new item - make sure a SelectedItemChanged event is fired in any case
                // Even if this means that we have to deselect/select the one and the same item
                if (itemSource.IsSelected == true)
                {
                    itemSource.IsSelected = false;
                }

                itemSource.IsSelected = true;

                // Lets enable this to get back to business for next selection
                treeView.PreviewMouseDown += uiElement_PreviewMouseDown;
            }
        }
Exemplo n.º 2
0
        /// <summary>
        /// This method is called when the selection changed event occurs. The sender should be the control
        /// on which this behaviour is attached - so we convert the sender into a <seealso cref="UIElement"/>
        /// and receive the Command through the <seealso cref="GetChangedCommand"/> getter listed above.
        ///
        /// The <paramref name="e"/> parameter contains the standard EventArgs data,
        /// which is unpacked and reales upon the bound command.
        ///
        /// This implementation supports binding of delegate commands and routed commands.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void Selection_Changed(object sender, RoutedPropertyChangedEventArgs <object> e)
        {
            var uiElement = sender as TreeView;

            // Sanity check just in case this was somehow send by something else
            if (uiElement == null)
            {
                return;
            }

            ICommand changedCommand = TreeViewSelectionChangedBehavior.GetChangedCommand(uiElement);

            // There may not be a command bound to this after all
            if (changedCommand == null)
            {
                return;
            }

            ////if ((e.NewValue == null && e.NewValue == null))
            ////  return;
            ////else
            ////{
            ////  // Actual value did not really change
            ////  if ((e.NewValue != null && e.NewValue != null))
            ////  {
            ////    if ((e.NewValue == e.NewValue))
            ////    return;
            ////  }
            ////}

            // Check whether this attached behaviour is bound to a RoutedCommand
            if (changedCommand is RoutedCommand)
            {
                // Execute the routed command
                (changedCommand as RoutedCommand).Execute(e.NewValue, uiElement);
            }
            else
            {
                // Execute the Command as bound delegate
                changedCommand.Execute(e.NewValue);
            }
        }