public static void Update()
 {
     while (true)
     {
         Task.Run(() =>
         {
             if (localService.ToDoItems.Count > 0)
             {
                 lock (locker)
                 {
                     for (int i = 0; i < localService.ToDoItems.Count; i++)
                     {
                         if (localService.ToDoItems[i].MessageType == MessageType.Add)
                         {
                             WorkWithJson(localService.ToDoItems[i]);
                         }
                         else if (localService.ToDoItems[i].MessageType == MessageType.Delete)
                         {
                             remoteService.DeleteItem(localService.ToDoItems[i].item.ToDoId);
                             localService.AllToDoItems.Remove(localService.ToDoItems[i]);
                             JSONWorker.Add(localService.AllToDoItems);
                         }
                         else if (localService.ToDoItems[i].MessageType == MessageType.UpDate)
                         {
                             WorkWithJson(localService.ToDoItems[i]);
                         }
                     }
                     localService.ToDoItems.Clear();
                 }
             }
         });
     }
 }
 private static void WorkWithJson(ToDoToServer model)
 {
     remoteService.CreateItem(model.item);
     localService.AllToDoItems.Remove(model);
     localService.AddItemExist(model.item);
     JSONWorker.Add(localService.AllToDoItems);
 }