ContextMenuItemClick

ContextMenuItemClick event fires when the user right clicks on a node that have associated context menu and clicks on a context menu item. Use the RadTreeViewContextMenuEventArgs.MenuItem property to get or set the clicked-on menu item properties. Use the RadTreeViewContextMenuEventArgs.Node property to get or set the clicked-on Node properties.

protected void RadTreeView1_ContextMenuItemClick(object sender, Telerik.Web.UI.RadTreeViewContextMenuEventArgs e)
{
    if (e.MenuItem.Text == "Delete" && e.Node.Category == "File")
    {
        e.Node.Remove();
    }
}       

Protected Sub RadTreeView1_ContextMenuItemClick(ByVal sender As Object, ByVal e As Telerik.Web.UI.RadTreeViewContextMenuEventArgs)
    If e.MenuItem.Text = "Delete" AndAlso e.Node.Category = "File" Then
        e.Node.Remove()
    End If
End Sub