How to delete data in Mobile Services - Windows Store App (Windows Azure)

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

using Microsoft.WindowsAzure.MobileServices;
using Newtonsoft.Json;
using Windows.UI.Popups;

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238

namespace myApp
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    /// 
    public class MyMember
    {
        public int Id { get; set; }

        [JsonProperty(PropertyName = "username")]
        public string Username { get; set; }

        [JsonProperty(PropertyName = "password")]
        public string Password { get; set; }

        [JsonProperty(PropertyName = "name")]
        public string Name { get; set; }

        [JsonProperty(PropertyName = "tel")]
        public string Tel { get; set; }

        [JsonProperty(PropertyName = "email")]
        public string Email { get; set; }
    }

    public sealed partial class MainPage : Page
    {

        private MobileServiceCollection<MyMember, MyMember> items;
        private IMobileServiceTable<MyMember> memberTable = App.MobileService.GetTable<MyMember>();

        public MainPage()
        {
            this.InitializeComponent();     
        }

    
        /// </summary>
        /// <param name="e">Event data that describes how this page was reached.  The Parameter
        /// property is typically used to configure the page.</param>
        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            RefreshMemberItems();
        }

        private async void RefreshMemberItems()
        {
            try
            {
                items = await memberTable.ToCollectionAsync();
            }
            catch (MobileServiceInvalidOperationException e)
            {
                throw e;
            }

            myListbox.ItemsSource = items;
        }

        private async void ClickDelete(object sender, RoutedEventArgs e)
        {
            Button btnDel = (Button)e.OriginalSource;


            var msgDialog = new MessageDialog("Are you Want to Continue?", "Confirmation Message");
            msgDialog.Commands.Add(new UICommand("Yes", (command) =>
            {
                DeleteItem(btnDel.Tag.ToString());
            }));
            msgDialog.Commands.Add(new UICommand("No", (command) =>
            {
                //
            }));
            await msgDialog.ShowAsync();

        }

        private async void DeleteItem(String id)
        {

            try
            {
                //** Get Item for Delete ***/
                items = await memberTable
                .Where(memberItem => memberItem.Id == Convert.ToInt32(id))
                .ToCollectionAsync();

                //*** Delete ***/
                MyMember member = items[0];
                await memberTable.DeleteAsync(member);
                RefreshMemberItems();
            }
            catch (MobileServiceInvalidOperationException e)
            {
                throw e;
            }

        }
        
    }
}