public async void OnAdd(object sender, EventArgs e)
        {
            var todo = new TodoItem { Name = newItemName.Text };
            await AddItem(todo);

            newItemName.Text = string.Empty;
            newItemName.Unfocus();
        }
 public async Task SaveTaskAsync(TodoItem item)
 {
     if (item.Id == null)
     {
         await todoTable.InsertAsync(item);
     }
     else
     {
         await todoTable.UpdateAsync(item);
     }
     
 }
 async Task CompleteItem(TodoItem item)
 {
     item.Done = true;
     await manager.SaveTaskAsync(item);
     todoList.ItemsSource = await manager.GetTodoItemsAsync();
 }
 // Data methods
 async Task AddItem(TodoItem item)
 {
     await manager.SaveTaskAsync(item);
     todoList.ItemsSource = await manager.GetTodoItemsAsync();
 }