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TreeViewItem.ExpandSubtree Method

Expands the TreeViewItem control and all its child TreeViewItem elements.

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)

member ExpandSubtree : unit -> unit

The following examples show how to find the selected TreeViewItem and expand it and all of it child items. The following XAML creates a TreeView and populates it with some data.

    <XmlDataProvider x:Key="myCompany" XPath="Company/Employee">
        <Company xmlns="">
          <Employee Name="Don Hall">
            <Employee Name="Alice Ciccu">
              <Employee Name="David Pelton">
                <Employee Name="Vivian Atlas"/>
              <Employee Name="Jeff Price">
                <Employee Name="Kari Hensien"/>
              <Employee Name="Andy Jacobs"/>
            <Employee Name="Bill Malone">
              <Employee Name="Maurice Taylor">
                <Employee Name="Sunil Uppal">
                  <Employee Name="Qiang Wang"/>

    <!-- Bind the HierarchicalDataTemplate.ItemsSource property to the employees under
         each Employee element. -->
    <HierarchicalDataTemplate x:Key="EmployeeTemplate" 
                              ItemsSource="{Binding XPath=Employee}">
      <TextBlock Text="{Binding XPath=@Name}"/>

  <TreeView Name="treeView1"
            ItemsSource="{Binding Source={StaticResource myCompany}}" 
            ItemTemplate="{StaticResource EmployeeTemplate}"/>
  <Button Name="expandSelect" 
            Content="Expand _Selected Item"


The following code traverses the TreeView to find the selected TreeViewItem and then calls ExpandSubtree to display all child items of the selected TreeViewItem.


The GetTreeViewItem method only works for TreeViewItem controls that are not virtualized. To learn how to find a TreeViewItem that may be virtualized, see How to: Find a TreeViewItem in a TreeView.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4
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