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稳扎稳打Silverlight(19) - 2.0通信之调用REST服务,处理JSON格式, XML格式, RSS/ATOM格式的数据


作者:webabcd


介绍
Silverlight 2.0 调用REST服务,处理JSON格式, XML格式, RSS/ATOM格式的数据
    通过 System.Net.WebClient 类调用 REST 服务
    通过 System.Json 命名控件下的类处理 JSON 数据
    通过 System.Xml.Linq 命名空间下的类(LINQ to XML)处理 XML 数据
    通过 System.ServiceModel.Syndication 命名空间下的类处理 RSS/ATOM 数据


在线DEMO
http://www.cnblogs.com/webabcd/archive/2008/10/09/1307486.html


示例
1、调用 REST 服务,返回 JSON 数据
REST.cs(WCF创建的REST服务)
using System;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activation;

using System.ServiceModel.Web;
using System.Collections.Generic;
using System.Text;
using System.IO;

/// <summary>
/// 提供 REST 服务的类
/// 注:Silverlight只支持 GET 和 POST
/// </summary>

[ServiceContract]
[AspNetCompatibilityRequirements(RequirementsMode 
= AspNetCompatibilityRequirementsMode.Allowed)]
public class REST
{
    
/// <summary>
    
/// 用于演示返回 JSON(对象) 的 REST 服务
    
/// </summary>
    
/// <param name="name"></param>
    
/// <returns></returns>

    [OperationContract]
    [WebGet(UriTemplate 
= "User/{name}/json", ResponseFormat = WebMessageFormat.Json)]
    
public User HelloJson(string name)
    
{
        
return new User { Name = name, DayOfBirth = new DateTime(1980214) };
    }


    
/// <summary>
    
/// 用于演示返回 JSON(集合) 的 REST 服务
    
/// </summary>
    
/// <returns></returns>

    [OperationContract]
    [WebGet(UriTemplate 
= "Users/json", ResponseFormat = WebMessageFormat.Json)]
    
public List<User> HelloJson2()
    
{
        
return new List<User> 
        

            
new User(){ Name = "webabcd01", DayOfBirth = new DateTime(198011) },
            
new User(){ Name = "webabcd02", DayOfBirth = new DateTime(198022) },
            
new User(){ Name = "webabcd03", DayOfBirth = new DateTime(198033) },
        }
;
    }

}


Json.xaml
<UserControl x:Class="Silverlight20.Communication.Json"
    xmlns
="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x
="http://schemas.microsoft.com/winfx/2006/xaml">
    
<StackPanel HorizontalAlignment="Left" Width="600">
    
        
<TextBox x:Name="txtMsgJson" Margin="5" />
        
<TextBox x:Name="txtMsgJson2" Margin="5" /> 
        
    
</StackPanel>
</UserControl>

Json.xaml.cs
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.IO;

namespace Silverlight20.Communication
{
    
public partial class Json : UserControl
    
{
        
public Json()
        
{
            InitializeComponent();

            
// 演示如何处理 JSON(对象)
            JsonDemo();

            
// 演示如何处理 JSON(集合)
            JsonDemo2();
        }


        
/// <summary>
        
/// 演示如何处理 JSON(对象)
        
/// </summary>

        void JsonDemo()
        
{
            
// REST 服务的 URL
            Uri uri = new Uri("http://localhost:3036/REST.svc/User/webabcd/json", UriKind.Absolute);

            
// 实例化 WebClient
            System.Net.WebClient client = new System.Net.WebClient();

            client.DownloadStringCompleted 
+= new DownloadStringCompletedEventHandler(json_DownloadStringCompleted);
            client.DownloadStringAsync(uri);

            txtMsgJson.Text 
= "读取 JSON(对象) 数据中。。。";
        }


        
void json_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        
{
            
if (e.Error != null)
            
{
                
// 发生错误的话,则打印出来
                txtMsgJson.Text = e.Error.ToString();
                
return;
            }


            
// 将获得的字符串转换为 JSON(对象)
            var buffer = System.Text.Encoding.UTF8.GetBytes(e.Result);
            var ms 
= new MemoryStream(buffer);
            var jsonObject 
= System.Json.JsonObject.Load(ms) as System.Json.JsonObject;

            txtMsgJson.Text 
= e.Result + "\r\n";
            
// 解析 JSON(对象)
            txtMsgJson.Text += string.Format("姓名: {0}, 生日: {1}",
                (
string)jsonObject["Name"],
                ((DateTime)jsonObject[
"DayOfBirth"]).ToString("yyyy-MM-dd"));

            
/* 
             * 总结:
             * JsonObject - 一个具有零或多个 key-value 对的无序集合。继承自抽象类 JsonValue
             *     JsonObject.Load(Stream) - 将指定的字符串流反序列化为 JSON 对象(CLR可用的类型)
             *     JsonObject[key] - JsonObject 索引器,获取 JsonObject 的指定key的value
             *     JsonObject.ContainsKey(key) - JsonObject 对象内是否具有指定的key
             
*/

        }


        
/// <summary>
        
/// 演示如何处理 JSON(集合)
        
/// </summary>

        void JsonDemo2()
        
{
            
// REST 服务的 URL
            Uri uri = new Uri("http://localhost:3036/REST.svc/Users/json", UriKind.Absolute);

            
// 实例化 WebClient
            System.Net.WebClient client = new System.Net.WebClient();

            client.DownloadStringCompleted 
+= new DownloadStringCompletedEventHandler(json2_DownloadStringCompleted);
            client.DownloadStringAsync(uri);

            txtMsgJson2.Text 
= "读取 JSON(集合) 数据中。。。";
        }


        
void json2_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        
{
            
if (e.Error != null)
            
{
                
// 发生错误的话,则打印出来
                txtMsgJson2.Text = e.Error.ToString();
                
return;
            }


            
// 将获得的字符串转换为 JSON(集合)
            var buffer = System.Text.Encoding.UTF8.GetBytes(e.Result);
            var ms 
= new MemoryStream(buffer);
            var jsonArray 
= System.Json.JsonArray.Load(ms) as System.Json.JsonArray;

            txtMsgJson2.Text 
= e.Result + "\r\n";
            txtMsgJson2.Text 
+= string.Format("姓名: {0}, 生日: {1}",
                (
string)jsonArray.First()["Name"],
                ((DateTime)jsonArray.Single(p 
=> p["Name"== "webabcd02")["DayOfBirth"]).ToString("yyyy-MM-dd"));

            
/* 
             * 总结:
             * JsonArray - 一个具有零或多个 JsonValue(抽象类,JsonObject和JsonArray都继承自此类) 对象的有序序列
             *     JsonArray.Load(Stream) - 将指定的字符串流反序列化为 JSON 对象(CLR可用的类型)
             *     JsonArray[index] - JsonArray 索引器,获取 JsonArray 的指定索引的 JsonValue
             *     JsonArray 支持 LINQ
             
*/

        }

    }

}



2、调用 REST 服务,返回 XML 数据
REST.cs(WCF创建的REST服务)
using System;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activation;

using System.ServiceModel.Web;
using System.Collections.Generic;
using System.Text;
using System.IO;

/// <summary>
/// 提供 REST 服务的类
/// 注:Silverlight只支持 GET 和 POST
/// </summary>

[ServiceContract]
[AspNetCompatibilityRequirements(RequirementsMode 
= AspNetCompatibilityRequirementsMode.Allowed)]
public class REST
{
    
/// <summary>
    
/// 用于演示返回 XML(对象) 的 REST 服务
    
/// </summary>
    
/// <param name="name"></param>
    
/// <returns></returns>

    [OperationContract]
    [WebGet(UriTemplate 
= "User/{name}/xml", ResponseFormat = WebMessageFormat.Xml)]
    
public User HelloXml(string name)
    
{
        
return new User { Name = name, DayOfBirth = new DateTime(1980214) };
    }


    
/// <summary>
    
/// 用于演示返回 XML(集合) 的 REST 服务
    
/// </summary>
    
/// <returns></returns>

    [OperationContract]
    [WebGet(UriTemplate 
= "Users/xml", ResponseFormat = WebMessageFormat.Xml)]
    
public List<User> HelloXml2()
    
{
        
return new List<User> 
        

            
new User(){ Name = "webabcd01", DayOfBirth = new DateTime(198011) },
            
new User(){ Name = "webabcd02", DayOfBirth = new DateTime(198022) },
            
new User(){ Name = "webabcd03", DayOfBirth = new DateTime(198033) },
        }
;
    }

}


Xml.xaml
<UserControl x:Class="Silverlight20.Communication.Xml"
    xmlns
="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x
="http://schemas.microsoft.com/winfx/2006/xaml">
    
<StackPanel HorizontalAlignment="Left" Width="600">

        
<TextBox x:Name="txtMsgXml" Margin="5" />
        
<TextBox x:Name="txtMsgXml2" Margin="5" />

    
</StackPanel>
</UserControl>

Xml.xaml.cs
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.Xml.Linq;
using System.IO;

namespace Silverlight20.Communication
{
    
public partial class Xml : UserControl
    
{
        
public Xml()
        
{
            InitializeComponent();

            
// 演示如何处理 XML(对象)
            XmlDemo();

            
// 演示如何处理 XML(集合)
            XmlDemo2();
        }


        
/// <summary>
        
/// 演示如何处理 XML(对象)
        
/// </summary>

        void XmlDemo()
        
{
            
// REST 服务的 URL
            Uri uri = new Uri("http://localhost:3036/REST.svc/User/webabcd/xml", UriKind.Absolute);

            
// 实例化 WebClient
            System.Net.WebClient client = new System.Net.WebClient();

            client.DownloadStringCompleted 
+= new DownloadStringCompletedEventHandler(xml_DownloadStringCompleted);
            client.DownloadStringAsync(uri);

            txtMsgXml.Text 
= "读取 XML(对象) 数据中。。。";
        }


        
void xml_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        
{
            
if (e.Error != null)
            
{
                
// 发生错误的话,则打印出来
                txtMsgXml.Text = e.Error.ToString();
                
return;
            }


            
// 将获得的字符串转换为 XML(对象)
            var buffer = System.Text.Encoding.UTF8.GetBytes(e.Result);
            var ms 
= new MemoryStream(buffer);

            XElement xmlObject 
= XElement.Load(ms);

            txtMsgXml.Text 
= e.Result + "\r\n";
            XNamespace ns 
= "http://webabcd.cnblogs.com/";
            txtMsgXml.Text 
+= string.Format("姓名: {0}, 生日: {1}",
                (
string)xmlObject.Element(ns + "Name"),
                ((DateTime)xmlObject.Element(ns 
+ "DayOfBirth")).ToString("yyyy-MM-dd"));

            
/* 
             * 总结:
             * XElement - 表示一个 XML 元素
             *     XElement.Element - XML 元素内的 XML 元素
             *     XElement.Attribute - XML 元素内的 XML 属性
             *     XElement.Load(Stream) - 使用指定流创建一个 XElement 对象
             *     XElement.Parse(String) - 解析指定的 XML 字符串为一个 XElement 对象
             * XAttribute - 表示一个 XML 属性
             
*/

        }


        
/// <summary>
        
/// 演示如何处理 XML(集合)
        
/// </summary>

        void XmlDemo2()
        
{
            
// REST 服务的 URL
            Uri uri = new Uri("http://localhost:3036/REST.svc/Users/xml", UriKind.Absolute);

            
// 实例化 WebClient
            System.Net.WebClient client = new System.Net.WebClient();

            client.DownloadStringCompleted 
+= new DownloadStringCompletedEventHandler(xml2_DownloadStringCompleted);
            client.DownloadStringAsync(uri);

            txtMsgXml2.Text 
= "读取 XML(集合) 数据中。。。";
        }


        
void xml2_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        
{
            
if (e.Error != null)
            
{
                
// 发生错误的话,则打印出来
                txtMsgXml2.Text = e.Error.ToString();
                
return;
            }


            
// 将获得的字符串转换为 XML(集合)
            XDocument xmlObject = XDocument.Parse(e.Result);

            txtMsgXml2.Text 
= e.Result + "\r\n";
            XNamespace ns 
= "http://webabcd.cnblogs.com/";
            var obj 
= from p in xmlObject.Elements(ns + "ArrayOfUser").Elements(ns + "User")
                      
where p.Element(ns + "Name").Value == "webabcd02"
                      select 
new { Name = (string)p.Element(ns + "Name"), DayOfBirth = (DateTime)p.Element(ns + "DayOfBirth") };
            
            txtMsgXml2.Text 
+= string.Format("姓名: {0}, 生日: {1}",
                obj.First().Name,
                obj.First().DayOfBirth.ToString(
"yyyy-MM-dd"));


            
/* 
             * 总结:
             * LINQ to XML 相当的方便
             
*/

        }

    }

}



3、调用 REST 服务,返回 Rss/Atom 数据
Proxy.aspx.cs(返回指定的url地址的内容的服务)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Proxy : System.Web.UI.Page
{
    
protected void Page_Load(object sender, EventArgs e)
    
{
        
// 获取某个 url 地址的 html 并在页面上输出

        
string url = Request.QueryString["url"];

        System.Net.WebClient client 
= new System.Net.WebClient();
        client.Encoding 
= System.Text.Encoding.UTF8;

        Response.Write(client.DownloadString(url));
        Response.End();
    }

}


RssAtom.xaml
<UserControl x:Class="Silverlight20.Communication.RssAtom"
    xmlns
="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x
="http://schemas.microsoft.com/winfx/2006/xaml">
    
<StackPanel HorizontalAlignment="Left" >

        
<TextBox x:Name="txtMsgRss" Width="600" Margin="5" />

        
<StackPanel Orientation="Horizontal">
        
            
<ListBox x:Name="list" Width="300" Margin="5" SelectionChanged="list_SelectionChanged">
                
<ListBox.ItemTemplate>
                    
<DataTemplate>
                        
<TextBlock Text="{Binding Title.Text}"></TextBlock>
                    
</DataTemplate>
                
</ListBox.ItemTemplate>
            
</ListBox>

            
<TextBlock x:Name="detail" Width="300" Margin="5" Text="{Binding Summary.Text}" TextWrapping="Wrap" />
            
        
</StackPanel>
        
    
</StackPanel>
</UserControl>

RssAtom.xaml.cs
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.Xml;
using System.IO;
using System.ServiceModel.Syndication;

namespace Silverlight20.Communication
{
    
public partial class RssAtom : UserControl
    
{
        
public RssAtom()
        
{
            InitializeComponent();

            
// 演示如何处理 Rss/Atom
            RssDemo();
        }


        
/// <summary>
        
/// 演示如何处理 Rss/Atom
        
/// </summary>

        void RssDemo()
        
{
            
// 让一个代理页面去请求相关的 Rss/Atom(如果用Silverlight直接去请求,则需要在目标域的根目录下配置策略文件)
            Uri uri = new Uri("http://localhost:3036/Proxy.aspx?url=http://webabcd.cnblogs.com/rss", UriKind.Absolute);

            
// 实例化 WebClient
            System.Net.WebClient client = new System.Net.WebClient();

            client.DownloadStringCompleted 
+= new DownloadStringCompletedEventHandler(rss_DownloadStringCompleted);
            client.DownloadStringAsync(uri);

            txtMsgRss.Text 
= "读取 RSS 数据中。。。";
        }


        
void rss_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        
{
            
if (e.Error != null)
            
{
                
// 发生错误的话,则打印出来
                txtMsgRss.Text = e.Error.ToString();
                
return;
            }


            
// 将获得的字符串转换为 XmlReader
            var buffer = System.Text.Encoding.UTF8.GetBytes(e.Result);
            var ms 
= new MemoryStream(buffer);
            XmlReader reader 
= XmlReader.Create(ms);

            
// 从指定的 XmlReader 中加载,以生成 SyndicationFeed
            SyndicationFeed feed = SyndicationFeed.Load(reader);

            
// 设置 list 的数据源为 Rss/Atom 的项集合(SyndicationFeed.Items)
            list.ItemsSource = feed.Items;
            txtMsgRss.Text 
= e.Result + "\r\n";
        }


        
private void list_SelectionChanged(object sender, SelectionChangedEventArgs e)
        
{
            
// 设置 detail 的数据上下文为 Rss/Atom 的指定项(SyndicationItem)
            detail.DataContext = list.SelectedItem as SyndicationItem;
        }

    }

}



OK
[源码下载]