RadControls for WPF
Contents

The RadTreeView API offers BringIntoView support through the following methods:

When you invoke any of these methods, the RadTreeView will attempt to bring the provided item into view.

BringIndexIntoView()

Important

The BringIndexIntoView() method can only work for immediate items. However, please note that the method won't be able to bring a RadTreeViewItem into view before the item containers have been generated.

Consider the following example. A RadTreeView is data bound to a collection of business objects.

CopyXAML
<Grid x:Name="LayoutRoot"
        Background="White">
    <Grid.Resources>
        <DataTemplate x:Key="treeViewTemplate">
            <TextBlock Text="{Binding Title}" />
        </DataTemplate>
    </Grid.Resources>
    <telerik:RadTreeView x:Name="RadTreeView">
        <telerik:RadTreeViewItem x:Name="RadTreeViewItem"
                                            Header="MyItems"
                                            ItemTemplate="{StaticResource treeViewTemplate}">
        </telerik:RadTreeViewItem>
    </telerik:RadTreeView>
</Grid>
CopyC#
public class MyViewModel 
{
    private static int idCounter;
    private string title;
    public MyViewModel()
    {
        this.Id = idCounter++;
    }
    public int Id
    {
        get;
        protected set;
    }
    public String Title
    {
        get
        {
            return this.title;
        }
        set
        {
            if ( this.title != value )
            {
                this.title = value;
            }
        }
    }
}
//.....
RadTreeViewItem.ItemsSource = Enumerable.Range( 1, 40 ).Select( i => new MyViewModel()
{
    Title = "Item " + i
} ).ToList();
CopyVB.NET
Public Class MyViewModel
 Private Shared idCounter As Integer
 Private m_title As String
 Public Sub New()
  Me.Id = System.Math.Max(System.Threading.Interlocked.Increment(idCounter),idCounter - 1)
 End Sub
 Public Property Id() As Integer
  Get
   Return m_Id
  End Get
  Protected Set
   m_Id = Value
  End Set
 End Property
 Private m_Id As Integer
 Public Property Title() As [String]
  Get
   Return Me.m_title
  End Get
  Set
   If Me.m_title <> value Then
    Me.m_title = value
   End If
  End Set
 End Property
End Class

If you want to programmatically scroll to the "Item 20" (thus bringing this item into view), you could try the following scenario:

CopyC#
private void BringItemIntoView()
{
    this.RadTreeViewItem.BringIndexIntoView( 20 );
}
CopyVB.NET
Private Sub BringItemIntoView()
    Me.RadTreeViewItem.BringIndexIntoView(20)
End Sub

And the result will be:

BringItemIntoView()

RadTreeView offers a second method which does exactly the same thing as the BringIndexIntoView() method. That's the BringItemIntoView() method.

CopyC#
private void BringItemIntoView()
{
  MyViewModel viewModel = dataSource.First( v => v.Title == "Item 20" );
  this.RadTreeViewItem.BringItemIntoView( viewModel );
}
CopyVB.NET
Private Sub Button_Click(sender As Object, e As RoutedEventArgs)
    Dim viewModel As MyViewModel = dataSource.First(Function(v) v.Title = "Item 20")
    Me.RadTreeViewItem.BringItemIntoView(viewModel)
End Sub
Important

Please keep in mind that the BringItemIntoView() method can only work for immediate items and only as long as all RadTreeViewItem containers have been generated.

The BringItemIntoView() method makes an internal call to the BringIntexIntoView() method and this is why it is better to consider using the BringIndexIntoView() method instead whenever possible.

BringPathIntoView()

Important

The BringPathIntoView() method can be used even in scenarios where not all RadTreeViewItem containers are generated. This is possible due to its implementation which makes sure that the RadTreeView has loaded its containers, before starting a recursive search through its items. This makes it the best choice for bringing virtualized items into view.

As the main purpose of this method is to allow you to bring virtualized items into view, you need to make sure that your view models can build a path to each RadTreeViewItem. This is important as the BringPathIntoView() method recursively traverses the hierarchy of data items displayed inside the RadTreeView to search for an item based on its path.

Another important note about the implementation of the method is that it uses the TextSearch.TextPath attached property to match the path to the RadTreeViewItem containers.

Note

The TextSearch.TextPath attached property is part of the Telerik.Windows.Controls namespace and this is why you can reach it through the following alias: xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation" like this: <telerik:RadTreeView telerik:TextSearch.TextPath="Name"/>

Consider the following RadTreeView definition:

CopyXAML
<telerik:RadTreeView x:Name="myTreeView" Width="300" IsVirtualizing="True" telerik:TextSearch.TextPath="Name">
    <telerik:RadTreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding Children}">
            <TextBlock Text="{Binding Name}" />
        </HierarchicalDataTemplate>
    </telerik:RadTreeView.ItemTemplate>
</telerik:RadTreeView>

If the business items displayed in the RadTreeView are described with the following classes:

CopyC#
public class MainViewModel : ObservableCollection<DataItem>
{
    public MainViewModel()
    {
        for (int i = 0; i < 25; i++)
        {
            DataItem item = new DataItem() { Name = String.Format("Item {0}", i) };
            for (int j = 0; j < 3; j++)
            {
                item.Children.Add(new DataItem { Name = String.Format("Item {0}.{1}", i, j) });
            }
            this.Add(item);
        }
    }
}

public class DataItem
{
    public string Name { get; set; }
    public ObservableCollection<DataItem> Children { get; set; }

    public DataItem()
    {
        this.Children = new ObservableCollection<DataItem>();
    }
}
CopyVB.NET
Public Class MainViewModel
    Inherits ObservableCollection(Of DataItem)
    Public Sub New()
        For i As Integer = 0 To 24
            Dim item As New DataItem() With {.Name = [String].Format("Item {0}", i)}
            For j As Integer = 0 To 2
                item.Children.Add(New DataItem() With {.Name = [String].Format("Item {0}.{1}", i, j)})
            Next
            Me.Add(item)
        Next
    End Sub
End Class

Public Class DataItem
    Public Property Name() As String
        Get
            Return itemName
        End Get
        Set
            itemName = Value
        End Set
    End Property
    Private itemName As String
    Public Property Children() As ObservableCollection(Of DataItem)
        Get
            Return itemChildren
        End Get
        Set
            itemChildren = Value
        End Set
    End Property
    Private itemChildren As ObservableCollection(Of DataItem)

    Public Sub New()
        Me.Children = New ObservableCollection(Of DataItem)()
    End Sub
End Class
Rad Tree View-Bring Path Into View-Tree View Def

You can bring an item into view like this:

CopyC#
public partial class Example : UserControl
{
    public Example()
    {
        InitializeComponent();
        myTreeView.ItemsSource = new MainViewModel();
        string path = "Item 20\\Item 20.1";
        myTreeView.BringPathIntoView(path);
    }
}
CopyVB.NET
Public Partial Class Example
    Inherits UserControl
    Public Sub New()
        InitializeComponent()
        myTreeView.ItemsSource = New MainViewModel()
        Dim path As String = "Item 20\Item 20.1"
        myTreeView.BringPathIntoView(path)
    End Sub
End Class
Tip

You can find a complete solution demonstrating the BringPathIntoView() method implementation in this tutorial.

See Also