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Expanded Event
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TreeViewItem.Expanded Event

Occurs when the IsExpanded property changes from false to true.

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public event RoutedEventHandler Expanded
<object Expanded="RoutedEventHandler" .../>

Identifier field

ExpandedEvent

Routing strategy

Bubbling

Delegate

RoutedEventHandler

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

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
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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