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

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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

介绍

Silverlight 2.0 详解WebRequest和WebResponse，对指定的URI做GET和POST请求，以及接收其响应

    HttpWebRequest - 对指定的 URI 发出请求

        Create() - 初始化一个 WebRequest

        BeginGetResponse() - 开始对指定 URI 资源做异步请求

        EndGetResponse() - 结束对指定 URI 资源做异步请求

    HttpWebResponse - 对指定的 URI 做出响应

        GetResponseStream() - 获取响应的数据流

在线DEMO

<a href="http://webabcd.blog.51cto.com/1787395/342779">http://webabcd.blog.51cto.com/1787395/342779</a>

示例

1、对指定的URI做GET请求以及接收响应

WebRequestGet.xaml

&lt;UserControl x:Class="Silverlight20.Communication.WebRequestGet" 

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

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

        &lt;StackPanel HorizontalAlignment="Left" Margin="5"&gt; 

                &lt;TextBlock x:Name="lblMsg" /&gt; 

        &lt;/StackPanel&gt; 

&lt;/UserControl&gt;

WebRequestGet.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.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; 

        } 

}

2、对指定的URI做POST请求以及接收响应

WebRequestPost.xaml

&lt;UserControl x:Class="Silverlight20.Communication.WebRequestPost" 

WebRequestPost.xaml.cs

        public partial class WebRequestPost : UserControl 

                // 接收 POST 方式数据的 REST 服务 

                string _url = "http://localhost:3036/REST.svc/PostUser"; 

                public WebRequestPost() 

                        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) 

                        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“&amp;”分隔 

                        streamWriter.Write("name=webabcd"); 

                        streamWriter.Close(); 

                                response = request.EndGetResponse(result); 

                        // 调用 UI 线程 

                         *         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 

                        if (response != null &amp;&amp; response.StatusCode == HttpStatusCode.OK) 

                                        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()); 

OK

     本文转自webabcd 51CTO博客，原文链接：http://blog.51cto.com/webabcd/343128，如需转载请自行联系原作者