public static void HideCheckBox(this TreeNode node)
 {
     TreeViewExtensions.TVITEM tVITEM = default(TreeViewExtensions.TVITEM);
     tVITEM.hItem     = node.Handle;
     tVITEM.mask      = 8;
     tVITEM.stateMask = 61440;
     tVITEM.state     = 0;
     TreeViewExtensions.SendMessage(node.TreeView.Handle, 4415, IntPtr.Zero, ref tVITEM);
 }
 private static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, ref TreeViewExtensions.TVITEM lParam);