稳扎稳打Silverlight(21) - 2.0通信之WebRequest和WebResponse, 对指定的URI发出请求以及接收响应

<UserControl x:Class="Silverlight20.Communication.WebRequestGet" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"> 
        <StackPanel HorizontalAlignment="Left" Margin="5"> 
         
                <TextBlock x:Name="lblMsg" /> 
                 
        </StackPanel> 
</UserControl>

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.Threading; 
using System.IO; 
 
namespace Silverlight20.Communication 
{ 
         public partial  class WebRequestGet : UserControl 
        { 
                 // 接收 GET 方式数据的 REST 服务 
                 string _url =  "http://localhost:3036/REST.svc/Users/json"; 
 
                // 异常信息 
                string _exception = ""; 
                 
                // SynchronizationContext - 同步上下文管理类 
                SynchronizationContext _syncContext; 
 
                public WebRequestGet() 
                { 
                        InitializeComponent(); 
 
                        Demo(); 
                } 
 
                void Demo() 
                { 
                        // SynchronizationContext.Current - 当前线程的同步上下文 
                        _syncContext = SynchronizationContext.Current; 
 
                        /* 
                         * HttpWebRequest - 对指定的 URI 发出请求 
                         *         HttpWebRequest.Create(uri) - 初始化一个 WebRequest 
                         *         HttpWebRequest.BeginGetResponse(AsyncCallback callback, Object state) - 开始对指定 URI 资源做异步请求 
                         *                 AsyncCallback callback - System.AsyncCallback 委托。异步操作完成时调用的回调方法 
                         *                 Object state - 包含此异步请求的对象。即相应的 HttpWebRequest 对象 
                         *         HttpWebRequest.Abort() - 取消该异步请求 
                         *         HttpWebRequest.Accept - HTTP 头的 Accept    部分 
                         *         HttpWebRequest.ContentType - HTTP 头的 ContentType 部分 
                         *         HttpWebRequest.Headers - HTTP 头的 key/value 对集合 
                         *         HttpWebRequest.Method - HTTP 方法（只支持GET和POST） 
                         *         HttpWebRequest.RequestUri - 所请求的 URI 
                         *         HttpWebRequest.HaveResponse - 是否接收到了指定 URI 的响应 
                         *         HttpWebRequest.AllowReadStreamBuffering - 是否对从 Internet 资源接收的数据做缓冲处理。默认值为true，将数据缓存在客户端内存中，以便随时被应用程序读取 
                         */ 
 
                        HttpWebRequest request = WebRequest.Create( 
                                new Uri(_url, UriKind.Absolute)) as HttpWebRequest; 
                        request.Method = "GET"; 
                        request.BeginGetResponse(new AsyncCallback(ResponseCallback), request); 
                } 
 
                private void ResponseCallback(IAsyncResult result) 
                { 
                        // IAsyncResult.AsyncState - AsyncCallback 传过来的对象 
                        HttpWebRequest request = result.AsyncState as HttpWebRequest; 
 
                        WebResponse response = null; 
 
                        try 
                        { 
                                // HttpWebRequest.EndGetResponse(IAsyncResult) - 结束对指定 URI 资源做异步请求 
                                //         返回值为 WebResponse 对象 
                                response = request.EndGetResponse(result) as HttpWebResponse; 
                        } 
                        catch (Exception ex) 
                        { 
                                _exception = ex.ToString(); 
                        } 
 
                        // SynchronizationContext.Post(SendOrPostCallback d, Object state) - 将异步消息发送到该同步上下文中 
                        //         SendOrPostCallback d - System.Threading.SendOrPostCallback 委托 
                        //         Object state - 需要传递的参数 
                        _syncContext.Post(GetResponse, response); 
                } 
 
                private void GetResponse(object state) 
                { 
                        /* 
                         * HttpWebResponse - 对指定的 URI 做出响应 
                         *         GetResponseStream() - 获取响应的数据流 
                         */ 
 
                        HttpWebResponse response = state as HttpWebResponse; 
 
                        if (response != null) 
                        { 
                                Stream responseStream = response.GetResponseStream(); 
                                using (StreamReader sr = new StreamReader(responseStream)) 
                                { 
                                        lblMsg.Text = sr.ReadToEnd(); 
                                } 
                        } 
                        else 
                        { 
                                lblMsg.Text = _exception; 
                        } 
                } 
        } 
}

<UserControl x:Class="Silverlight20.Communication.WebRequestPost" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"> 
        <StackPanel HorizontalAlignment="Left" Margin="5"> 
         
                <TextBlock x:Name="lblMsg" /> 
         
        </StackPanel> 
</UserControl>

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.Threading; 
using System.IO; 
 
namespace Silverlight20.Communication 
{ 
         public partial  class WebRequestPost : UserControl 
        { 
                 // 接收 POST 方式数据的 REST 服务 
                 string _url =  "http://localhost:3036/REST.svc/PostUser"; 
 
                // 异常信息 
                string _exception = ""; 
 
                // SynchronizationContext - 同步上下文管理类 
                SynchronizationContext _syncContext; 
 
                public WebRequestPost() 
                { 
                        InitializeComponent(); 
 
                        Demo(); 
                } 
 
                void Demo() 
                { 
                        _syncContext = SynchronizationContext.Current; 
 
                        HttpWebRequest request = WebRequest.Create( 
                                new Uri(_url, UriKind.Absolute)) as HttpWebRequest; 
 
                        request.Method = "POST"; 
 
                        // BeginGetRequestStream(AsyncCallback callback, Object state) - 向指定的 URI 资源发送数据的流的异步请求 
                        //         AsyncCallback callback - System.AsyncCallback 委托 
                        //         Object state - 包含此异步请求的对象。即相应的 HttpWebRequest 对象 
                        IAsyncResult asyncResult = request.BeginGetRequestStream( 
                                new AsyncCallback(RequestStreamCallback), request); 
                } 
 
                private void RequestStreamCallback(IAsyncResult result) 
                { 
                        HttpWebRequest request = result.AsyncState as HttpWebRequest; 
                        request.ContentType = "application/x-www-form-urlencoded"; 
 
                        // HttpWebRequest.EndGetRequestStream(IAsyncResult) - 返回用于将数据写入某 URI 资源的 Stream 
                        Stream requestStream = request.EndGetRequestStream(result); 
 
                        StreamWriter streamWriter = new StreamWriter(requestStream); 
 
                        // byte[] postdata = System.Text.Encoding.UTF8.GetBytes("name=webabcd"); 
                        // 多个参数用“&”分隔 
                        streamWriter.Write("name=webabcd"); 
 
                        streamWriter.Close(); 
 
                        request.BeginGetResponse(new AsyncCallback(ResponseCallback), request); 
                } 
 
                private void ResponseCallback(IAsyncResult result) 
                { 
                        HttpWebRequest request = result.AsyncState as HttpWebRequest; 
 
                        WebResponse response = null; 
 
                        try 
                        { 
                                response = request.EndGetResponse(result); 
                        } 
                        catch (Exception ex) 
                        { 
                                _exception = ex.ToString(); 
                        } 
 
                        // 调用 UI 线程 
                        _syncContext.Post(GetResponse, response); 
                } 
 
                private void GetResponse(object state) 
                { 
                        /* 
                         * HttpWebResponse - 对指定的 URI 做出响应 
                         *         GetResponseStream() - 获取响应的数据流 
                         *         ContentLength - 接收的数据的内容长度 
                         *         ContentType - HTTP 头的 ContentType 部分 
                         *         Method - HTTP 方法 
                         *         ResponseUri - 响应该请求的 URI 
                         *         StatusCode - 响应状态 [System.Net.HttpStatusCode枚举] 
                         *                 HttpStatusCode.OK - HTTP 状态为 200 
                         *                 HttpStatusCode.NotFound - HTTP 状态为 404 
                         *         StatusDescription - 响应状态的说明 
                         */ 
 
                        HttpWebResponse response = state as HttpWebResponse; 
 
                        if (response != null && response.StatusCode == HttpStatusCode.OK) 
                        { 
                                Stream responseStream = response.GetResponseStream(); 
                                using (StreamReader sr = new StreamReader(responseStream)) 
                                { 
                                        lblMsg.Text = string.Format("接收的数据的内容长度：{0}\r\nHTTP 头的 ContentType 部分：{1}\r\nHTTP 方法：{2}\r\n响应该请求的 URI：{3}\r\n响应状态：{4}\r\n响应状态的说明：{5}\r\n响应的结果：{6}\r\n", 
                                                response.ContentLength, 
                                                response.ContentType, 
                                                response.Method, 
                                                response.ResponseUri, 
                                                response.StatusCode, 
                                                response.StatusDescription, 
                                                sr.ReadToEnd()); 
                                } 
                        } 
                        else 
                        { 
                                lblMsg.Text = _exception; 
                        } 
                } 
        } 
}