Thread t1 = new Thread(() => ThreadRun(tr,rt));
t1.Start();

  private void ThreadRun(TreeView tr, RTBContextMenu rt)
        {
            bool temp = true;
            int idex = -1;
            while (temp)
            {
                if (rt.GetIsShow() == false)
                {
                    idex = rt.GetIdex();
                    tr.Dispatcher.BeginInvoke(new
 
 Action(() =>
                    {


                    }));
                    temp = false;
                }
                else
                    Thread.Sleep(20);
            }
        }