TreeView.AfterExpand Event

Occurs after the tree node is expanded.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
Public Event AfterExpand As TreeViewEventHandler

For more information about how to handle events, see Handling and Raising Events.

The following code example demonstrates the use of this member. In the example, an event handler reports on the occurrence of the AfterExpand event. This report helps you learn when the event occurs and can assist you in debugging. To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.

To run the example code, paste it into a project that contains an instance of type TreeView named TreeView1. Then ensure that the event handler is associated with the AfterExpand event.

Private Sub TreeView1_AfterExpand(sender as Object, e as TreeViewEventArgs) _ 
     Handles TreeView1.AfterExpand

    Dim messageBoxVB as New System.Text.StringBuilder()
    messageBoxVB.AppendFormat("{0} = {1}", "Node", e.Node)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "Action", e.Action)
    messageBoxVB.AppendLine()
    MessageBox.Show(messageBoxVB.ToString(),"AfterExpand Event")

End Sub

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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