TreeViewItem.ExpandSubtree Yöntem

Tanım

Ad Alanı:

System.Windows.Controls

Bütünleştirilmiş Kod:

PresentationFramework.dll

TreeViewItem Denetimi ve tüm alt TreeViewItem öğelerini genişletir.

public:
 void ExpandSubtree();

public void ExpandSubtree ();

member this.ExpandSubtree : unit -> unit

Public Sub ExpandSubtree ()

Örnekler

Aşağıdaki örneklerde, seçilen TreeViewItem öğeyi bulma ve bunu ve tüm alt öğeleri genişletme adımları gösterilir. Aşağıdaki XAML bir TreeView oluşturur ve bunu bazı verilerle doldurur.

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

    <!-- 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}"/>
    </HierarchicalDataTemplate>

  </StackPanel.Resources>
  <TreeView Name="treeView1"
            ItemsSource="{Binding Source={StaticResource myCompany}}" 
            ItemTemplate="{StaticResource EmployeeTemplate}"/>
  <Button Name="expandSelect" 
            Margin="5,0,0,0"
            Content="Expand _Selected Item"
            Click="expandSelected_Click"/>

</StackPanel>

Aşağıdaki kod, seçileni bulmak için öğesinin TreeView çapraz geçişini yapar ve ardından seçili TreeViewItem TreeViewItemöğesinin tüm alt öğelerini görüntülemek için öğesini çağırırExpandSubtree.

Not

GetTreeViewItem yöntemi yalnızca sanallaştırılmayan denetimler için TreeViewItem çalışır. Sanallaştırılabilecek bir TreeViewItem öğesini bulmayı öğrenmek için bkz . Nasıl yapılır: TreeView'da TreeViewItem Bulma.

private void expandSelected_Click(object sender, RoutedEventArgs e)
{
    if (treeView1.SelectedItem == null)
    {
        return;
    }

    TreeViewItem tvi = GetTreeViewItem(treeView1, treeView1.SelectedItem);

    if (tvi != null)
    {
        tvi.ExpandSubtree();
    }
}

// Traverse the TreeView to find the TreeViewItem 
// that corresponds to the selected item.
private TreeViewItem GetTreeViewItem(ItemsControl parent, object item)
{
    // Check whether the selected item is a direct child of 
    // the parent ItemsControl.
    TreeViewItem tvi =
        parent.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;

    if (tvi == null)
    {
        // The selected item is not a child of parent, so check
        // the child items of parent.
        foreach (object child in parent.Items)
        {
            TreeViewItem childItem = 
                parent.ItemContainerGenerator.ContainerFromItem(child) as TreeViewItem;

            if (childItem != null)
            {
                // Check the next level for the appropriate item.
                tvi = GetTreeViewItem(childItem, item);
            }
        }
    }
    return tvi;
}

Private Sub expandSelected_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If treeView1.SelectedItem Is Nothing Then
        Exit Sub
    End If

    Dim tvi As TreeViewItem =
        GetTreeViewItem(treeView1, treeView1.SelectedItem)

    If tvi IsNot Nothing Then
        tvi.ExpandSubtree()
    End If
End Sub

' Traverse the TreeView to find the TreeViewItem 
' that corresponds to the selected item. 
Private Function GetTreeViewItem(ByVal parent As ItemsControl,
                                 ByVal item As Object) As TreeViewItem

    ' Check whether the selected item is a direct child of 
    ' the parent ItemsControl. 
    Dim tvi As TreeViewItem =
        TryCast(parent.ItemContainerGenerator.ContainerFromItem(item), TreeViewItem)

    If tvi Is Nothing Then
        ' The selected item is not a child of parent, so check 
        ' the child items of parent. 
        For Each child As Object In parent.Items
            Dim childItem As TreeViewItem =
                TryCast(parent.ItemContainerGenerator.ContainerFromItem(child), TreeViewItem)

            If childItem IsNot Nothing Then
                ' Check the next level for the appropriate item. 
                tvi = GetTreeViewItem(childItem, item)
            End If
        Next
    End If
    Return tvi
End Function