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

作者：webabcd

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

示例
1、对指定的URI做GET请求以及接收响应
WebRequestGet.xaml

<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>

</UserControl>

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

<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>

</UserControl>

WebRequestPost.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 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;

}

OK
[源码下载]

posted @ 2008-12-11 08:20 webabcd 阅读(6839) 评论(14) 编辑收藏举报

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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

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