private void List_ChatRooms_ItemCheck(object sender, ItemCheckEventArgs e)
 {
     if (e.NewValue == CheckState.Unchecked)
     {
         Manager.AddChannel(List_ChatRooms.Items[e.Index] as string);
     }
     else
     {
         Manager.RemoveChannel(List_ChatRooms.Items[e.Index] as string);
     }
 }