稳扎稳打Silverlight(56) - 4.0通信之与 WCF Data Services 进行通信

作者： webabcd
介绍
Silverlight 4.0 对 WCF Data Services 的支持：

DataServiceCollection<T> - 继承自 ObservableCollection<T>，用于将 WCF Data Services 提供的数据绑定到 Silverlight 控件上，当数据发生变化时可提供通知

在线DEMO
http://www.cnblogs.com/webabcd/archive/2010/08/09/1795417.html
示例
演示 Silverlight 4.0 与 WCF Data Services 之间的通信
1、服务端
MyWCFDataService.svc.cs

代码

@H_502_40@/* @H_502_40@
* WCF Data Services - 用于提供基于 OData 协议的数据服务
* OData 协议 - 开放数据协议（Open Data Protocol），其基于 REST-ful 协议，参考： http://www.odata.org/ @H_502_40@
@H_502_40@*/

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 Silverlight40.Web.Service
{
     public class MyWCFDataService : DataService < Model.northwindEntities >
    {
         public static void InitializeService(DataServiceConfiguration config)
        {
            config.SetEntitySetAccessRule( " * " , EntitySetRights.All);

             @H_502_40@// @H_502_40@ 指定对 Products, Categories, Orders 启用服务端分页，页大小为 3 @H_502_40@
            config.SetEntitySetPageSize( " Products " , 3 );
            config.SetEntitySetPageSize( " Categories " , 3 );
            config.SetEntitySetPageSize( " Orders " , 3 );

            config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
        }
    }
}

2、客户端
Demo.xaml

代码

< navigation:Page x:Class ="Silverlight40.WCFDataServices.Demo"
           xmlns ="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
           xmlns:x ="http://schemas.microsoft.com/winfx/2006/xaml"
           xmlns:d ="http://schemas.microsoft.com/expression/blend/2008"
           xmlns:mc ="http://schemas.openxmlformats.org/markup-compatibility/2006"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           xmlns:sdk ="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
           Title ="Demo Page" >
     < Grid x:Name ="LayoutRoot" >
         < StackPanel Orientation ="Vertical" HorizontalAlignment ="Left" >

             @H_502_40@
             < StackPanel Orientation ="Horizontal" >
                 < Button Name ="btnGetData" Content ="获取数据" Margin ="5" Click ="btnGetData_Click" />
             </ StackPanel >

             < TextBlock Text ="产品类别列表:" Margin ="5" />
             < sdk:DataGrid Name ="gridCategory" Margin ="5" Height ="200" Width ="400" AutoGenerateColumns ="False" ItemsSource =" {Binding} "
                       SelectionChanged ="gridCategory_SelectionChanged" >
                 < sdk:DataGrid.Columns >
                     < sdk:DataGridTextColumn Header ="类别ID" Binding =" {Binding CategoryID} " IsReadOnly ="True" />
                     < sdk:DataGridTextColumn Header ="类别名称" Binding =" {Binding CategoryName} " />
                 </ sdk:DataGrid.Columns >
             </ sdk:DataGrid >

             < TextBlock Text ="产品列表:" Margin ="5" />
             < sdk:DataGrid Name ="gridProduct" Margin ="5" Height ="200" Width ="400" AutoGenerateColumns ="False" ItemsSource =" {Binding} " >
                 < sdk:DataGrid.Columns >
                     < sdk:DataGridTextColumn Header ="产品ID" Binding =" {Binding ProductID} " IsReadOnly ="True" />
                     < sdk:DataGridTextColumn Header ="产品名称" Binding =" {Binding ProductName} " />
                     < sdk:DataGridTextColumn Header ="单价" Binding =" {Binding UnitPrice} " IsReadOnly ="True" />
                 </ sdk:DataGrid.Columns >
             </ sdk:DataGrid >

             < Button Name ="btnSave" Content ="保存" Margin ="5" Width ="400" Click ="btnSave_Click" />

             @H_502_40@
             < TextBlock Text ="订单列表:" Margin ="5,20,5,5" />
             < sdk:DataGrid Name ="gridOrder" Margin ="5" Height ="200" Width ="400" IsReadOnly ="True" AutoGenerateColumns ="False" ItemsSource =" {Binding} " >
                 < sdk:DataGrid.Columns >
                     < sdk:DataGridTextColumn Header ="订单ID" Binding =" {Binding OrderID} " />
                     < sdk:DataGridTextColumn Header ="客户ID" Binding =" {Binding CustomerID} " />
                 </ sdk:DataGrid.Columns >
             </ sdk:DataGrid >
             < TextBlock Name ="txtCurrentPageIndex" />
             < Button Name ="btnPrev" Content ="上一页" Margin ="5" Width ="400" />
             < Button Name ="btnNext" Content ="下一页" Margin ="5" Width ="400" />

         </ StackPanel >
     </ Grid >
</ navigation:Page >

Demo.xaml.cs

代码

@H_502_40@/* @H_502_40@
* 演示 Silverlight 4.0 与 WCF Data Services 之间的通信
*
* DataServiceCollection<T> - 继承自 ObservableCollection<T>。用于将 WCF Data Services 提供的数据绑定到 Silverlight 控件上，当数据发生变化时可提供通知
*     LoadAsync(IQueryable<T>) - 从数据服务上异步加载 IQueryable<T> 数据到 DataServiceCollection<T> 中（在 LoadCompleted 触发之前不能再调用此方法）
*     LoadAsync() - 当 DataServiceCollection<T> 表示为某实体的导航属性时，从数据服务上异步加载该数据（在 LoadCompleted 触发之前不能再调用此方法）
*     LoadCompleted - 异步加载完成后所触发的事件
*         LoadCompletedEventArgs - LoadCompleted 事件的事件参数
*         LoadCompletedEventArgs.QueryOperationResponse - 获取数据服务对改查询操作的响应
*             QueryOperationResponse.Error - 引发的异常
*             QueryOperationResponse.Headers -  HTTP 的响应头
*             QueryOperationResponse.Query - 对应的 DataServiceQuery（DataServiceQuery.RequestUri - 请求数据服务的 URI）对象
*             QueryOperationResponse.StatusCode - HTTP 的响应代码
*     Continuation - 返回一个 DataServiceQueryContinuation<T> 对象，该对象封装了当前查询结果的下一页的 URI
*         DataServiceQueryContinuation<T>.NextLinkUri - 当前查询结果的下一页的 URI
*     LoadNextPartialSetAsync() - 加载下一页数据到 DataServiceCollection<T> 中
*
* Silverlight 通过 ObservableCollection<T> 与 ADO.NET Data Services 1.0 进行通信详见 http://www.cnblogs.com/webabcd/archive/2009/03/12/1409281.html @H_502_40@
* WCF Data Services（ADO.NET Data Services 1.5）新特性详见 http://www.cnblogs.com/webabcd/archive/2010/06/11/1756071.html @H_502_40@
@H_502_40@*/

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 System.Windows.Navigation;

using Silverlight40.MyWCFDataServiceReference;
using System.Data.Services.Client;

namespace Silverlight40.WCFDataServices
{
     public partial class Demo : Page
    {
         private northwindEntities _context;
         private DataServiceCollection < Category > _categories;

         public Demo()
        {
            InitializeComponent();
        }

         protected override void OnNavigatedTo(NavigationEventArgs e)
        {
             @H_502_40@// @H_502_40@ 指定数据服务地址 @H_502_40@
            _context = new northwindEntities( new Uri( " Service/MyWCFDataService.svc " , UriKind.Relative));

            _categories = new DataServiceCollection < Category > ();
            _categories.LoadCompleted += new EventHandler < LoadCompletedEventArgs > (_categories_LoadCompleted);

             @H_502_40@// @H_502_40@ 演示如何通过 WCF Data Services 做服务端分页 @H_502_40@
            ServerPagingDemo();
        }

         @H_502_40@// @H_502_40@ 开始异步加载 Categories 数据 @H_502_40@
         private void btnGetData_Click( object sender, RoutedEventArgs e)
        {
            gridCategory.DataContext = null ;
            gridProduct.DataContext = null ;

             @H_502_40@// @H_502_40@ 加载 Categories 表中的全部数据 @H_502_40@
            var query = from c in _context.Categories select c;
            _categories.LoadAsync(query);

            btnGetData.IsEnabled = false ;
        }

         @H_502_40@// @H_502_40@ 异步加载 Categories 数据完成 @H_502_40@
         void _categories_LoadCompleted( object sender, LoadCompletedEventArgs e)
        {
             if (e.Error == null )
            {
                 if (_categories.Continuation != null )
                {
                     @H_502_40@// @H_502_40@ 在数据服务中 Categories 被服务端分页了，所以需要不断调用 LoadNextPartialSetAsync() ，以便加载全部的 Categories 数据 @H_502_40@
                    _categories.LoadNextPartialSetAsync();
                }
                 else
                {
                    gridCategory.DataContext = _categories;
                    gridCategory.Selectedindex = 0 ;

                    btnGetData.IsEnabled = true ;
                }
            }
             else
            {
                MessageBox.Show(e.Error.ToString());
                btnGetData.IsEnabled = true ;
            }
        }

         @H_502_40@// @H_502_40@ 开始异步加载指定 Category 下的 Products 数据 @H_502_40@
         private void gridCategory_SelectionChanged( object sender, SelectionChangedEventArgs e)
        {
            Category category = gridCategory.SelectedItem as Category;

             if (category != null )
            {
                 if (category.Products.Count == 0 )
                {
                    category.Products.LoadCompleted += new EventHandler < LoadCompletedEventArgs > (Products_LoadCompleted);

                     try
                    {
                         @H_502_40@// @H_502_40@ 加载实体的导航属性数据 @H_502_40@
                        category.Products.LoadAsync();
                    }
                     catch (InvalidOperationException ex)
                    {
                        MessageBox.Show(ex.ToString());
                    }
                }
                 else
                {
                    gridProduct.DataContext = category.Products;
                }
            }
        }

         @H_502_40@// @H_502_40@ 异步加载 Products 数据完成 @H_502_40@
         void Products_LoadCompleted( object sender, LoadCompletedEventArgs e)
        {
             if (e.Error == null )
            {
                DataServiceCollection < Product > products = sender as DataServiceCollection < Product > ;

                 if (products.Continuation != null )
                {
                     try
                    {
                        products.LoadNextPartialSetAsync();
                    }
                     catch (InvalidOperationException ex)
                    {
                        MessageBox.Show(ex.ToString());
                    }
                }
                 else
                {
                    gridProduct.DataContext = products;
                }
            }
             else
            {
                MessageBox.Show(e.Error.ToString());
            }
        }

         @H_502_40@// @H_502_40@ 异步保存 Categories 中的被更新的数据（包括增删改），由于 Products 是 Category 的导航属性，所以相关的 Products 的数据的更新也会被保存 @H_502_40@
         private void btnSave_Click( object sender, RoutedEventArgs e)
        {
             try
            {
                 @H_502_40@/* @H_502_40@
                 * northwindEntities - 继承自 DataServiceContext，在 VS 中引用服务后会自动生成这个对象
                 *     DataServiceContext.BeginSaveChanges() - 将有变化的数据提交至数据服务端进行更新
                 *     DataServiceContext.EndSaveChanges() - 获取 BeginSaveChanges() 操作的结果，返回一个 DataServiceResponse 类型的对象
                  @H_502_40@*/

                _context.BeginSaveChanges(SaveChangesOptions.Batch, OnChangesSaved, null );
            }
             catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

         @H_502_40@// @H_502_40@ 数据被异步保存后 @H_502_40@
         private void OnChangesSaved(IAsyncResult result)
        {
             bool error = false ;

             this .dispatcher.BeginInvoke(() =>
            {
                 try
                {
                    DataServiceResponse response = _context.EndSaveChanges(result);

                     foreach (ChangeOperationResponse changeResponse in response)
                    {
                         if (changeResponse.Error != null )
                            error = true ;
                    }

                     if ( ! error)
                    {
                        MessageBox.Show( " 数据更新成功 " );
                    }
                     else
                    {
                        MessageBox.Show( " 数据更新失败 " );
                    }
                }
                 catch (Exception ex)
                {
                    MessageBox.Show(ex.ToString());
                }
            });
        }

         private int _pageIndex = 0 ;
         private int _pageSize = 3 ;

         @H_502_40@// @H_502_40@ 演示如何通过 WCF Data Services 做服务端分页 @H_502_40@
         private void ServerPagingDemo()
        {
            BindOrder();

            btnNext.Click += (s, args) =>
            {
                _pageIndex ++ ;
                BindOrder();
            };

            btnPrev.Click += (s, args) =>
            {
                _pageIndex -- ;
                BindOrder();
            };
        }

         private void BindOrder()
        {
            txtCurrentPageIndex.Text = " 当前页索引： " + _pageIndex.ToString();

            var query = from o in _context.Orders select o;
            query = query.Skip(_pageIndex * _pageSize).Take(_pageSize);
            DataServiceCollection < Order > orders = new DataServiceCollection < Order > ();
            orders.LoadAsync(query);

            orders.LoadCompleted += (s, args) =>
            {
                gridOrder.DataContext = orders;
            };
        }
    }
}

OK
[源码下载]

稳扎稳打Silverlight(56) - 4.0通信之与 WCF Data Services 进行通信

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