BeforeCollapse Event

Occurs before an UltraTreeNode is collapsed.

Syntax

Visual Basic

'Declaration
 
Public Event BeforeCollapse As BeforeNodeChangedEventHandler

C#

public event BeforeNodeChangedEventHandler BeforeCollapse

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 is being collapsed.

Setting the System.ComponentModel.CancelEventArgs.Cancel property to true will prevent the UltraTreeNode from being collapsed.

Example

The following sample code illustrates some of the information available in the BeforeCollapse 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_BeforeCollapse(ByVal sender As Object, ByVal e As Infragistics.Win.UltraWinTree.CancelableNodeEventArgs) Handles ultraTree1.BeforeCollapse

    Dim sb As New System.Text.StringBuilder()

    sb.Append("Node: ")
    sb.Append(e.TreeNode.Key)
    sb.Append(" is about to be collapsed.")

    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_BeforeCollapse(object sender, Infragistics.Win.UltraWinTree.CancelableNodeEventArgs e)
{

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

	sb.Append("Node: ");
	sb.Append(e.TreeNode.Key);
	sb.Append(" is about to be collapsed.");

	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