HttpWebRequest和WebClient的区别

HttpWebRequest和WebClient的区别(From Linzheng)：

1,HttpWebRequest是个抽象类，所以无法new的，需要调用HttpWebRequest.Create();
2,其Method指定了请求类型，这里用的GET,还有POST；也可以指定ConentType;
3,其请求的Uri必须是绝对地址;
4,其请求是异步回调方式的，从BeginGetResponse开始，并通过AsyncCallback指定回调方法；
5,WebClient 方式使用基于事件的异步编程模型,在HTTP响应返回时引发的WebClient回调是在UI线程中调用的，因此可用于更新UI元素的属性，例如把 HTTP响应中的数据绑定到UI的指定控件上进行显示。HttpWebRequest是基于后台进程运行的，回调不是UI线程，所以不能直接对UI进行操作，通常使用Dispatcher.BeginInvoke()跟界面进行通讯。

  1 //body是要传递的参数,格式"roleId=1&uid=2"
  2 //post的cotentType填写:
  3 //"application/x-www-form-urlencoded"
  4 //soap填写:"text/xml; charset=utf-8"
  5 public static string PostHttp(string url, string body, string contentType)
  6 {
  7 HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
  8 
  9 httpWebRequest.ContentType = contentType;
 10 httpWebRequest.Method = "POST";
 11 httpWebRequest.Timeout = 20000;
 12 
 13 byte[] btBodys = Encoding.UTF8.GetBytes(body);
 14 httpWebRequest.ContentLength = btBodys.Length;
 15 httpWebRequest.GetRequestStream().Write(btBodys, 0, btBodys.Length);
 16 
 17 HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
 18 StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream());
 19 string responseContent = streamReader.ReadToEnd();
 20 
 21 httpWebResponse.Close();
 22 streamReader.Close();
 23 httpWebRequest.Abort();
 24 httpWebResponse.Close();
 25 
 26 return responseContent;
 27 }
 28 
 29 POST方法(httpWebRequest)
 30 
 31  
 32 
 33  
 34 
 35 /// <summary>
 36 /// 通过WebClient类Post数据到远程地址，需要Basic认证；
 37 /// 调用端自己处理异常
 38 /// </summary>
 39 /// <param name="uri"></param>
 40 /// <param name="paramStr">name=张三&age=20</param>
 41 /// <param name="encoding">请先确认目标网页的编码方式</param>
 42 /// <param name="username"></param>
 43 /// <param name="password"></param>
 44 /// <returns></returns>
 45 public static string Request_WebClient(string uri, string paramStr, Encoding encoding, string username, string password)
 46 {
 47 if (encoding == null)
 48 encoding = Encoding.UTF8;
 49 
 50 string result = string.Empty;
 51 
 52 WebClient wc = new WebClient();
 53 
 54 // 采取POST方式必须加的Header
 55 wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
 56 
 57 byte[] postData = encoding.GetBytes(paramStr);
 58 
 59 if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password))
 60 {
 61 wc.Credentials = GetCredentialCache(uri, username, password);
 62 wc.Headers.Add("Authorization", GetAuthorization(username, password));
 63 }
 64 
 65 byte[] responseData = wc.UploadData(uri, "POST", postData); // 得到返回字符流
 66 return encoding.GetString(responseData);// 解码 
 67 }
 68 
 69 POST方法(WebClient)
 70 
 71  
 72 
 73 public static string GetHttp(string url, HttpContext httpContext)
 74 {
 75 string queryString = "?";
 76 
 77 foreach (string key in httpContext.Request.QueryString.AllKeys)
 78 {
 79 queryString += key + "=" + httpContext.Request.QueryString[key] + "&";
 80 }
 81 
 82 queryString = queryString.Substring(0, queryString.Length - 1);
 83 
 84 HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url + queryString);
 85 
 86 httpWebRequest.ContentType = "application/json";
 87 httpWebRequest.Method = "GET";
 88 httpWebRequest.Timeout = 20000;
 89 
 90 //byte[] btBodys = Encoding.UTF8.GetBytes(body);
 91 //httpWebRequest.ContentLength = btBodys.Length;
 92 //httpWebRequest.GetRequestStream().Write(btBodys, 0, btBodys.Length);
 93 
 94 HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
 95 StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream());
 96 string responseContent = streamReader.ReadToEnd();
 97 
 98 httpWebResponse.Close();
 99 streamReader.Close();
100 
101 return responseContent;
102 }
103 
104 Get方法(HttpWebRequest)
105 
106  
107 
108  
109 
110  
111 
112 /// <summary>
113 /// 通过 WebRequest/WebResponse 类访问远程地址并返回结果，需要Basic认证；
114 /// 调用端自己处理异常
115 /// </summary>
116 /// <param name="uri"></param>
117 /// <param name="timeout">访问超时时间，单位毫秒；如果不设置超时时间，传入0</param>
118 /// <param name="encoding">如果不知道具体的编码，传入null</param>
119 /// <param name="username"></param>
120 /// <param name="password"></param>
121 /// <returns></returns>
122 public static string Request_WebRequest(string uri, int timeout, Encoding encoding, string username, string password)
123 {
124 string result = string.Empty;
125 
126 WebRequest request = WebRequest.Create(new Uri(uri));
127 
128 if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password))
129 {
130 request.Credentials = GetCredentialCache(uri, username, password);
131 request.Headers.Add("Authorization", GetAuthorization(username, password));
132 }
133 
134 if (timeout > 0)
135 request.Timeout = timeout;
136 
137 WebResponse response = request.GetResponse();
138 Stream stream = response.GetResponseStream();
139 StreamReader sr = encoding == null ? new StreamReader(stream) : new StreamReader(stream, encoding);
140 
141 result = sr.ReadToEnd();
142 
143 sr.Close();
144 stream.Close();
145 
146 return result;
147 }
148 
149 #region # 生成 Http Basic 访问凭证 #
150 
151 private static CredentialCache GetCredentialCache(string uri, string username, string password)
152 {
153 string authorization = string.Format("{0}:{1}", username, password);
154 
155 CredentialCache credCache = new CredentialCache();
156 credCache.Add(new Uri(uri), "Basic", new NetworkCredential(username, password));
157 
158 return credCache;
159 }
160 
161 private static string GetAuthorization(string username, string password)
162 {
163 string authorization = string.Format("{0}:{1}", username, password);
164 
165 return "Basic " + Convert.ToBase64String(new ASCIIEncoding().GetBytes(authorization));
166 }
167 
168 #endregion
169 
170 basic验证的WebRequest/WebResponse