Saturday, 25 July 2009

De-Selecting all Nodes in Silverlight TreeView

If you are wondering how you can de-select all Nodes in a Silverlight TreeView – here is one way to do it. Attach a a handler to the MouseLeftButtonUp as follows:

<Toolkit:TreeView MouseLeftButtonUp="TreeView_MouseUp"></Toolkit:TreeView>

And use the following event handler code:

private void TreeView_MouseUp(object sender, MouseButtonEventArgs e)
if (sender is TreeView && ((TreeView)sender).SelectedItem != null)
if(e.OriginalSource is Border)
((TreeViewItem)((TreeView)sender).SelectedItem).IsSelected = false;

If The expected behaviour is that you can click anywhere on the TreeView surface (of cource not on Any Node) and the currently selected Node will be de-selected.

If you have problems, make sure the Event Handler is actually being called when you press and release the mouse button on the TreeView – you can do this by placing a breakpoint in the event handler.

Friday, 24 July 2009

Accessing and Identifying objects in Silverlight ItemTemplate

One simple way to identify and access objects within an ItemTemplate is to Bind the Name of the object of interest to a String variable that is passed as part of the DataContext and attach EventHanler to Loaded event. The EventHandler will then Store the objects received as sender of the event into a Dictionary keyed on the object's Name.

Here is an example With TreeView within ListBox:

<UserControl xmlns:Toolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"  x:Class=""

mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
<Grid x:Name="LayoutRoot">
<ListBox x:Name="listBox" Margin="0,38,0,0" >
<Toolkit:TreeView x:Name="{Binding}" Loaded="TreeView_Loaded" ></Toolkit:TreeView>
<Button VerticalAlignment="Top" HorizontalAlignment="Center" Content="Load TreeView Items" Click="Button_Click"/>

And Here is the code Behind:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

public partial class MainPage : UserControl
Dictionary<System.String, TreeView> TreeViewChildren = new Dictionary<string,TreeView>();
List<String> ChildTreeViewNames = new List<string>();
public MainPage()

List<String> ChildTreeViewNames = new List<string> { "TreeView1", "TreeView2" };
listBox.ItemsSource = ChildTreeViewNames;


private void TreeView_Loaded(object sender, RoutedEventArgs e)
TreeViewChildren.Add((System.String)((TreeView)sender).Name, (TreeView)sender);

private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
TreeViewChildren["TreeView1"].Items.Add(new TreeViewItem() { Header = "Item1" });
TreeViewChildren["TreeView1"].Items.Add(new TreeViewItem() { Header = "Item2" });
TreeViewChildren["TreeView2"].Items.Add(new TreeViewItem() { Header = "Item3" });