private void DeleteCautationClient()
 {
     if (SelectedCautationClient != null)
     {
         if (ListofSelectedClients.IndexOf(SelectedCautationClient) > -1)
         {
             ListofSelectedClients.Remove(SelectedCautationClient);
         }
     }
 }
        private void NewClientSelected()
        {
            if (ListofSelectedClients.IndexOf(SelectedClient) <= -1)
            {
                if (SelectedClient != null)
                {
                    ListofSelectedClients.Add(SelectedClient);
                }
            }

            To = "";
        }