BeforeActivate Event

Occurs before a tree node is Activated.

Syntax

Visual Basic

'Declaration
 
Public Event BeforeActivate As BeforeNodeChangedEventHandler

C#

public event BeforeNodeChangedEventHandler BeforeActivate

Event Data

The event handler receives an argument of type CancelableNodeEventArgs containing data related to this event. The following CancelableNodeEventArgs properties provide information specific to this event.

Property	Description
Cancel (Inherited from System.ComponentModel.CancelEventArgs)
TreeNode	The UltraTreeNode (read-only)

Remarks

The CancelableNodeEventArgs.TreeNode property of the CancelableNodeEventArgs contains a reference to UltraTreeNode that will become the new ActiveNode.

Settng the System.ComponentModel.CancelEventArgs.Cancel property to true will prevent the node from activating.

Example

The following sample code illustrates some of the information available in the BeforeActivate event.

For an overview of how to handle events in Visual Basic or Visual C#, see Event Handlers in Visual Basic and Visual C#. For specific information and code examples illustrating how to consume events in your application, see Consuming Events in the .NET Framework Developer's Guide.

Visual Basic

Imports Infragistics.Win.UltraWinTree

Private Sub ultraTree1_BeforeActivate(ByVal sender As Object, ByVal e As Infragistics.Win.UltraWinTree.CancelableNodeEventArgs) Handles ultraTree1.BeforeActivate

    Dim sb As New System.Text.StringBuilder()

    If e.TreeNode Is Nothing Then
        sb.Append("No node is being activated.")
    Else
        sb.Append("Node: ")
        sb.Append(e.TreeNode.Key)
        sb.Append(" is being activated.")
    End If

    Debug.WriteLine(sb.ToString())

    ' Note : This action can be canceled by the following line of code.
    'e.Cancel = True

End Sub

C#

using System.Diagnostics;
using Infragistics.Win.UltraWinTree;

private void ultraTree1_BeforeActivate(object sender, Infragistics.Win.UltraWinTree.CancelableNodeEventArgs e)
{

	System.Text.StringBuilder sb = new System.Text.StringBuilder();

	if ( e.TreeNode == null )
	{
		sb.Append("No node is being activated.");
	}
	else
	{
		sb.Append("Node: ");
		sb.Append(e.TreeNode.Key);
		sb.Append(" is being activated.");
	}

	Debug.WriteLine( sb.ToString() );

	// Note : This action can be canceled by the following line of code.
	//e.Cancel = true;

}

Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2