private void RefreshList()
 {
     if (server != null && ServerSelect.Checked)
     {
         listView1.Items.Clear();
         AddItemToList("Server", server.GetLocalIP());
         var list = server.GetConnectedIP();
         for (int i = 0; i < list.Count; i++)
         {
             AddItemToList("Client", list[i]);
         }
     }
     if (client != null && ClientSelect.Checked)
     {
         listView1.Items.Clear();
         AddItemToList("Server", client.GetServerIP());
         var list = client.GetConnectedIP();
         if (list == null)
         {
             MessageBox.Show("Time Out");
             return;
         }
         for (int i = 0; i < list.Count; i++)
         {
             AddItemToList("Client", list[i]);
         }
     }
 }