NodeCheck
When the user selects or unselects a Node checkbox, the NodeCheck event fires. The RadTreeNodeEventArgs has a Node property that can be used to get the current Checked property value of that Node.
protected void RadTreeView1_NodeCheck(object sender, Telerik.Web.UI.RadTreeNodeEventArgs e)
{
e.Node.Text = e.Node.Checked.ToString();
}
Protected Sub RadTreeView1_NodeCheck(ByVal sender As Object, ByVal e As Telerik.Web.UI.RadTreeNodeEventArgs)
e.Node.Text = e.Node.Checked.ToString()
End Sub