与众不同 windows phone (29) - Communication（通信）之与 OData 服务通信

/*

 * 提供 OData 服务，详细说明请参见 WCF Data Services 的相关文章：http://www.cnblogs.com/webabcd/category/181636.html

 */

using System;

using System.Collections.Generic;

using System.Data.Services;

using System.Data.Services.Common;

using System.Linq;

using System.ServiceModel.Web;

using System.Web;

namespace Web.Communication

{

    // 出现异常时，返回详细的错误信息

    [System.ServiceModel.ServiceBehavior(IncludeExceptionDetailInFaults = true)]

    public class NorthwindService : DataService<NorthwindEntities>

    {

        public static void InitializeService(DataServiceConfiguration config)

        {

            // 全部实体全部权限

            config.SetEntitySetAccessRule("*", EntitySetRights.All);

            // 指定服务所支持的 OData 协议的最大版本

            config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;

        }

    }

}

/*

 * 调用 OData 服务的 ViewModel 层

 *

 * DataServiceCollection<T> - OData 服务的实体数据集合，添加、删除和更新数据时都会提供通知，继承自 ObservableCollection<T>

 *     Count - 实体数据集合中的实体数

 *     CollectionChangedCallback - 实体集合更改时调用的委托

 *     EntityChangedCallback - 实体更改时调用的委托

 *     Continuation - 是否还有下一页数据

 *     LoadAsync(IQueryable<T> query) - 通过指定的查询异步加载数据

 *     CancelAsyncLoad() - 取消异步加载请求

 *     LoadNextPartialSetAsync() - 加载下一页数据

 *     Detach() - 停止跟踪集合中的全部实体

 *     LoadCompleted - 异步数据加载完成后触发的事件

 *

 *

 * DataServiceState - 服务状态

 *     Serialize(DataServiceContext context, Dictionary<string, Object> collections) - 序列化 DataServiceContext 对象以及页面的相关数据

 *         注：引用 OData 服务后，会自动生成一个继承自 DataServiceContext 的代理类，如果需要序列化的话，则必须手动为其加上 [System.Runtime.Serialization.DataContract]

 *     Deserialize() - 反序列化，返回 DataServiceState 类型的数据

 *     Context - 相关的 DataServiceContext 对象

 *     RootCollections - 相关的数据

 *

 *

 * 注：

 * OData 服务的相关查询参数参见：http://msdn.microsoft.com/en-us/library/gg309461.aspx

 */

using System;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Ink;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using System.ComponentModel;

using Demo.NorthwindContext;

using System.Data.Services.Client;

using System.Linq;

using System.Collections.Generic;

namespace Demo.Communication.ODataClient.ViewModel

{

    public class MyViewModel : INotifyPropertyChanged

    {

        // 引用过来的 OData 服务

        private NorthwindEntities _context;

        // OData 服务地址

        private Uri _northwindUri = new Uri("http://localhost:15482/Communication/NorthwindService.svc/");

        // 相关数据，DataServiceCollection<T> 继承自 ObservableCollection<T>

        public DataServiceCollection<Category> Categories { get; private set; }

        public void LoadData()

        {

            _context = new NorthwindEntities(_northwindUri);

            // 实例化 DataServiceCollection<Category>，并注册相关事件

            Categories = new DataServiceCollection<Category>(_context);

            Categories.LoadCompleted += new EventHandler<LoadCompletedEventArgs>(Categories_LoadCompleted);

            // 获取全部 Categories 数据，并且一次请求带上 Categories 的所有 Products

            DataServiceQuery<Category> query = _context.Categories.Expand("Products");

            Categories.LoadAsync(query);

            NotifyPropertyChanged("Categories");

        }

        void Categories_LoadCompleted(object sender, LoadCompletedEventArgs e)

        {

            if (e.Error == null)

            {

                // 如果服务端有分页，则继续获取直至获取完全部数据

                if (Categories.Continuation != null)

                    Categories.LoadNextPartialSetAsync();

            }

            else

            {

                Deployment.Current.Dispatcher.BeginInvoke(delegate

                {

                    MessageBox.Show(e.Error.ToString());

                });

            }

        }

        // 新增产品数据

        public void AddProduct(Product product)

        {

            _context.AddToProducts(product);

            Categories.Single(p => p.CategoryID == product.CategoryID).Products.Add(product);

            SaveChanges();

        }

        // 删除产品数据

        public void DeleteProduct(Product product)

        {

            _context.DeleteObject(product);

            Categories.Single(p => p.CategoryID == product.CategoryID).Products.Remove(product);

            SaveChanges();

        }

        // 更新产品数据

        public void UpdateProduct(Product product)

        {

            _context.UpdateObject(product);

            SaveChanges();

        }

        public void SaveChanges()

        {

            // 异步向 OData 服务提交最近的数据变化

            _context.BeginSaveChanges(OnChangesSaved, _context);

        }

        private void OnChangesSaved(IAsyncResult result)

        {

            Deployment.Current.Dispatcher.BeginInvoke(delegate

            {

                _context = result.AsyncState as NorthwindEntities;

                try

                {

                    // 完成数据提交

                    _context.EndSaveChanges(result);

                }

                catch (Exception ex)

                {

                    MessageBox.Show(ex.ToString());

                }

            });

        }

        // 一个异步获取数据的例子，此 Demo 没用到此方法

        public void GetData()

        {

            // 查找 Products 里 ProductID 为 1 的数据

            var query = _context.CreateQuery<Product>("Products").AddQueryOption("$filter", "ProductID eq 1");

            // 异步请求 OData 服务

            query.BeginExecute(p =>

            {

                var myQuery = p.AsyncState as DataServiceQuery<Product>;

                try

                {

                    // 获取请求结果

                    var result = myQuery.EndExecute(p).First();

                    // 更新数据

                    _context.UpdateObject(result);

                    // 将更新后的结果提交到 OData 服务

                    SaveChanges();

                }

                catch (Exception ex)

                {

                    Deployment.Current.Dispatcher.BeginInvoke(delegate

                    {

                        MessageBox.Show(ex.ToString());

                    });

                }

            }, query);

        }

        // 序列化当前数据，Deactivated 保存此值到应用程序状态，参见 App.xaml.cs

        public string GetState()

        {

            var dict = new Dictionary<string, object>();

            dict["categories"] = Categories;

            return DataServiceState.Serialize(_context, dict);

        }

        // 恢复数据，当从 tombstone 状态进入 Activated 时，则从应用程序状态中恢复数据，参见 App.xaml.cs

        public void RestoreState(string appState)

        {

            Dictionary<string, object> dict;

            if (!string.IsNullOrEmpty(appState))

            {

                DataServiceState state = DataServiceState.Deserialize(appState);

                // 获取相关数据

                var context = state.Context as NorthwindEntities;

                dict = state.RootCollections;

                DataServiceCollection<Category> categories = dict["Categories"] as DataServiceCollection<Category>;

                // 恢复相关数据

                _context = context;

                Categories = categories;

                Categories.LoadCompleted += new EventHandler<LoadCompletedEventArgs>(Categories_LoadCompleted);

                NotifyPropertyChanged("Categories");

            }

        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged(string propertyName)

        {

            var propertyChanged = PropertyChanged;

            if (propertyChanged != null)

                propertyChanged(this, new PropertyChangedEventArgs(propertyName));

        }

    }

}

<Application

    x:Class="Demo.App"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"

    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"

    xmlns:odataViewModel="clr-namespace:Demo.Communication.ODataClient.ViewModel">

    <Application.Resources>

        <odataViewModel:MyViewModel x:Key="ODataViewModel" />

    </Application.Resources>

</Application>

        private void Application_Activated(object sender, ActivatedEventArgs e)

        {

            // 从 tombstone 状态返回，则恢复相关数据，参见：“调用 OData 服务”

            if (!e.IsApplicationInstancePreserved)

            {

                if (PhoneApplicationService.Current.State.ContainsKey("categoriesState"))

                {

                    var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

                    string categoriesState = PhoneApplicationService.Current.State["categoriesState"] as string;

                    vm.RestoreState(categoriesState);

                }

            }

        }

        private void Application_Deactivated(object sender, DeactivatedEventArgs e)

        {

            // 保存相关数据，参见：“调用 OData 服务”

            var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

            PhoneApplicationService.Current.State["categoriesState"] = vm.GetState();

        }

<phone:PhoneApplicationPage

    x:Class="Demo.Communication.ODataClient.Demo"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"

    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    FontFamily="{StaticResource PhoneFontFamilyNormal}"

    FontSize="{StaticResource PhoneFontSizeNormal}"

    Foreground="{StaticResource PhoneForegroundBrush}"

    SupportedOrientations="Portrait" Orientation="Portrait"

    mc:Ignorable="d" d:DesignHeight="696" d:DesignWidth="480"

    shell:SystemTray.IsVisible="True"

    DataContext="{Binding Source={StaticResource ODataViewModel}}"

    xmlns:controls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls">

    <phone:PhoneApplicationPage.Resources>

        <DataTemplate x:Key="item">

            <ListBox ItemsSource="{Binding Products}">

                <ListBox.ItemTemplate>

                    <DataTemplate>

                        <Grid Width="460" HorizontalAlignment="Center">

                            <Grid.ColumnDefinitions>

                                <ColumnDefinition Width="5*" />

                                <ColumnDefinition Width="5*" />

                            </Grid.ColumnDefinitions>

                            <StackPanel Orientation="Horizontal" VerticalAlignment="Center">

                                <TextBlock Text="{Binding ProductName}" />

                                <TextBlock Text="{Binding UnitPrice}" Margin="10 0 0 0" />

                            </StackPanel>

                            <StackPanel Orientation="Horizontal" Grid.Column="1" HorizontalAlignment="Right">

                                <Button x:Name="btnUpdate" Content="更新" Click="btnUpdate_Click" />

                                <Button x:Name="btnDelete" Content="删除" Click="btnDelete_Click" />

                            </StackPanel>

                        </Grid>

                    </DataTemplate>

                </ListBox.ItemTemplate>

            </ListBox>

        </DataTemplate>

        <DataTemplate x:Key="header">

            <TextBlock Text="{Binding CategoryName}" />

        </DataTemplate>

    </phone:PhoneApplicationPage.Resources>

    <Grid x:Name="LayoutRoot" Background="Transparent">

        <controls:Pivot x:Name="pivot"

            Title="产品列表"

            ItemTemplate="{StaticResource item}"

            HeaderTemplate="{StaticResource header}"

            ItemsSource="{Binding Categories}">

        </controls:Pivot>

    </Grid>

    <phone:PhoneApplicationPage.ApplicationBar>

        <shell:ApplicationBar Mode="Default" IsVisible="True">

            <shell:ApplicationBarIconButton x:Name="btnAd" IconUri="/ApplicationBarDemo/Assets/appbar.add.rest.png" Text="添加" Click="btnAd_Click" />

        </shell:ApplicationBar>

    </phone:PhoneApplicationPage.ApplicationBar>

</phone:PhoneApplicationPage>

/*

 * 调用 OData 服务的 View 层

 */

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using Microsoft.Phone.Controls;

using Demo.Communication.ODataClient.ViewModel;

using Demo.NorthwindContext;

namespace Demo.Communication.ODataClient

{

    public partial class Demo : PhoneApplicationPage

    {

        public Demo()

        {

            InitializeComponent();

            this.Loaded += new RoutedEventHandler(Demo_Loaded);

        }

        void Demo_Loaded(object sender, RoutedEventArgs e)

        {

            // 加载数据

            var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

            vm.LoadData();

        }

        private void btnDelete_Click(object sender, RoutedEventArgs e)

        {

            var product = (sender as Button).DataContext as Product;

            // 删除指定的产品数据

            var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

            vm.DeleteProduct(product);

        }

        private void btnUpdate_Click(object sender, RoutedEventArgs e)

        {

            // 更新指定的产品数据

            var product = (sender as Button).DataContext as Product;

            product.UnitPrice = 8.88m;

            var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

            vm.UpdateProduct(product);

        }

        private void btnAd_Click(object sender, EventArgs e)

        {

            // 在指定的类别下添加一个新的产品数据

            var category = pivot.SelectedItem as Category;

            Product product = new Product();

            product.CategoryID = category.CategoryID;

            product.ProductName = "测试" + new Random().Next(, );

            product.UnitPrice = 6.66m;

            product.Discontinued = false;

            var vm = App.Current.Resources["ODataViewModel"] as MyViewModel;

            vm.AddProduct(product);

        }

    }

}