TreeViewItem.Expanded Event

Definition

Namespace:

System.Windows.Controls

Assembly:

PresentationFramework.dll

Occurs when the IsExpanded property changes from false to true.

public:
 event System::Windows::RoutedEventHandler ^ Expanded;

public event System.Windows.RoutedEventHandler Expanded;

member this.Expanded : System.Windows.RoutedEventHandler 

Public Custom Event Expanded As RoutedEventHandler 

Event Type

RoutedEventHandler

Examples

The following example shows how to assign an event handler for the Expanded event to a TreeViewItem and how to define the event handler in the code-behind.

<TreeViewItem Header="Employee1"
              Name="Employee1Data" 
              IsExpanded="True" 
              Collapsed="OnCollapsed" 
              Expanded="OnExpanded">
  <TreeViewItem Header="Work Days" 
                Name="EmployeeWorkDays"
                IsSelected="True">
    <TreeViewItem Header="Tuesday" />
    <TreeViewItem Header="Friday"/>
  </TreeViewItem>
</TreeViewItem>
<TreeViewItem Header="Employee2" 
              Name="Employee2Data">
  <TreeViewItem Header="Work Days" 
                Name="emp2WorkDays" 
                Selected="GetSchedule"
                Unselected="SetSchedule">
    <TreeViewItem Header="Monday" />
    <TreeViewItem Header="Wednesday"/>
  </TreeViewItem>
</TreeViewItem>

private void OnExpanded(object sender, RoutedEventArgs e)
{
    //Perform actions when the TreeViewItem is expanded
}

Private Sub OnExpanded(ByVal sender As Object, ByVal e As RoutedEventArgs)
    'Perform actions when the TreeViewItem is expanded
End Sub

Remarks

This event occurs when a TreeViewItem is expanded so that its child elements are visible.

Routed Event Information

Item	Value
Identifier field	ExpandedEvent
Routing strategy	Bubbling
Delegate	RoutedEventHandler

See also

• IsExpanded
• Collapsed