Infragistics2.Win.UltraWinTree.v8.1
BeforeActivate Event
See Also  Example
Infragistics.Win.UltraWinTree Namespace > UltraTree Class : BeforeActivate Event

Occurs before a tree node is Activated.

Syntax

Visual Basic (Declaration) 
Public Event BeforeActivate() As BeforeNodeChangedEventHandler
C# 
public event BeforeNodeChangedEventHandler BeforeActivate()

Remarks

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

Settng the 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 BasicCopy Code
    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#Copy Code
       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;

       }

See Also