Silverlight HttpWebRequest工具类
原文地址:http://www.cameronalbert.com/post/2008/03/HttpWebRequest-Helper-for-Silverlight-2.aspx
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using System;using System.Collections.Generic;using System.IO;using System.Windows;using System.Windows.Browser;using System.Windows.Controls;using System.Windows.Documents;using System.Windows.Ink;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Animation;using System.Windows.Shapes;using System.Net;namespace Lionsguard{ public class HttpHelper { private HttpWebRequest Request { get; set; } public Dictionary<string, string> PostValues { get; private set; } public event HttpResponseCompleteEventHandler ResponseComplete; private void OnResponseComplete(HttpResponseCompleteEventArgs e) { if (this.ResponseComplete != null) { this.ResponseComplete(e); } } public HttpHelper(Uri requestUri, string method, params KeyValuePair<string, string>[] postValues) { this.Request = (HttpWebRequest)WebRequest.Create(requestUri); this.Request.ContentType = "application/x-www-form-urlencoded"; this.Request.Method = method; this.PostValues = new Dictionary<string, string>(); if (postValues != null && postValues.Length > 0) { foreach (var item in postValues) { this.PostValues.Add(item.Key, item.Value); } } } public void Execute() { this.Request.BeginGetRequestStream(new AsyncCallback(HttpHelper.BeginRequest), this); } private static void BeginRequest(IAsyncResult ar) { HttpHelper helper = ar.AsyncState as HttpHelper; if (helper != null) { if (helper.PostValues.Count > 0) { using (StreamWriter writer = new StreamWriter(helper.Request.EndGetRequestStream(ar))) { foreach (var item in helper.PostValues) { writer.Write("{0}={1}&", item.Key, HttpUtility.UrlEncode(item.Value)); } } } helper.Request.BeginGetResponse(new AsyncCallback(HttpHelper.BeginResponse), helper); } } private static void BeginResponse(IAsyncResult ar) { HttpHelper helper = ar.AsyncState as HttpHelper; if (helper != null) { HttpWebResponse response = (HttpWebResponse)helper.Request.EndGetResponse(ar); if (response != null) { Stream stream = response.GetResponseStream(); if (stream != null) { using (StreamReader reader = new StreamReader(stream)) { helper.OnResponseComplete(new HttpResponseCompleteEventArgs(reader.ReadToEnd())); } } } } } } public delegate void HttpResponseCompleteEventHandler(HttpResponseCompleteEventArgs e); public class HttpResponseCompleteEventArgs : EventArgs { public string Response { get; set; } public HttpResponseCompleteEventArgs(string response) { this.Response = response; } }}?使用方法?
private void ProcessCommand(short cmd, string msg) { App app = App.Current as App; HttpHelper helper = new HttpHelper(app.ServerUri, "POST", new KeyValuePair<string, string>("authKey", app.AuthKey), new KeyValuePair<string, string>("cmd", cmd.ToString()), new KeyValuePair<string, string>("msg", msg)); helper.ResponseComplete += new HttpResponseCompleteEventHandler(this.CommandComplete); helper.Execute(); } private void CommandComplete(HttpResponseCompleteEventArgs e) { txtAlert.Text = e.Response; }?
如果您使用的是VBScript的话，工具类代码如下：
Public Class HttpHelper Private Property Request() As HttpWebRequest Get Return _Request End Get Set(ByVal value As HttpWebRequest) _Request = value End Set End Property Private _Request As HttpWebRequest Public Property PostValues() As Dictionary(Of String, String) Get Return _PostValues End Get Private Set(ByVal value As Dictionary(Of String, String)) _PostValues = value End Set End Property Private _PostValues As Dictionary(Of String, String) Public Event ResponseComplete As HttpResponseCompleteEventHandler Private Sub OnResponseComplete(ByVal e As HttpResponseCompleteEventArgs) RaiseEvent ResponseComplete(e) End Sub Public Sub New(ByVal requestUri As Uri, ByVal method As String, ByVal ParamArray postValues As KeyValuePair(Of String, String)()) Me.Request = DirectCast(WebRequest.Create(requestUri), HttpWebRequest) Me.Request.ContentType = "application/x-www-form-urlencoded" Me.Request.Method = method Me.PostValues = New Dictionary(Of String, String)() For Each item In postValues Me.PostValues.Add(item.Key, item.Value) Next End Sub Public Sub Execute() Me.Request.BeginGetRequestStream(New AsyncCallback(AddressOf HttpHelper.BeginRequest), Me) End Sub Private Shared Sub BeginRequest(ByVal ar As IAsyncResult) Dim helper As HttpHelper = TryCast(ar.AsyncState, HttpHelper) If helper IsNot Nothing Then Using writer As New StreamWriter(helper.Request.EndGetRequestStream(ar)) For Each item In helper.PostValues writer.Write("{0}={1}&", item.Key, HttpUtility.UrlEncode(item.Value)) Next End Using helper.Request.BeginGetResponse(New AsyncCallback(AddressOf HttpHelper.BeginResponse), helper) End If End Sub Private Shared Sub BeginResponse(ByVal ar As IAsyncResult) Dim helper As HttpHelper = TryCast(ar.AsyncState, HttpHelper) If helper IsNot Nothing Then Dim response As HttpWebResponse = DirectCast(helper.Request.EndGetResponse(ar), HttpWebResponse) If response IsNot Nothing Then Dim stream As Stream = response.GetResponseStream() If stream IsNot Nothing Then Using reader As New StreamReader(stream) helper.OnResponseComplete(New HttpResponseCompleteEventArgs(reader.ReadToEnd())) End Using End If End If End If End SubEnd ClassPublic Delegate Sub HttpResponseCompleteEventHandler(ByVal e As HttpResponseCompleteEventArgs)Public Class HttpResponseCompleteEventArgs Inherits EventArgs Public Property Response() As String Get Return _Response End Get Set(ByVal value As String) _Response = value End Set End Property Private _Response As String Public Sub New(ByVal response As String) Me.Response = response End SubEnd Class?
? 在做自动更新程序时想省点事，直接使用HttpWebRequest和HttpWebResponse从服务器上下载更新的文件。 使用时注意Close响应流:
使用HttpWebRequest.GetResponse()取得HttpWebResponse接口后，必须要记得调用HttpWebResponse.close关闭流。
如果使用HttpWebResponse.GetResponseStream()取得响应流的话，那么使用此Stream的Close方法来关闭也是一样。
如果是使用StreamReader.ReadToEnd()从响应流中读取文本，则在读取完内容后会自动关闭流。
MSDN中这样描述HttpWebResponse.close方法：
Close 方法关闭响应流并释放到资源的连接以供其他请求重用。
您必须调用 Stream.Close 或 HttpWebResponse.Close 方法来关闭流并释放连接以供重用。不必同时调用 Stream.Close 和 HttpWebResponse.Close，但这样做不会导致错误。关闭该流失败会导致应用程序用尽连接。
连接限制好像是最大2个，不知是IIS的限制还是本地HttpWebRequest的限制。?