C#实现通过HttpWebRequest发送POST请求实现网站自动登陆

如某个页面有个如下的表单（Form）： 

< form name = " form1 "  action = " http://www.breakn.com/login.asp "  method = " post " >
< input type = " text "  name = " userid "  value = "" >
< input type = " password "  name = " password "  value = "" >
</ form >  

从表单可看到表单有两个表单域，一个是userid另一个是password，所以以POST形式提交的数据应该包含有这两项。
其中POST的数据格式为：
表单域名称1 = 值1 & 表单域名称2 = 值2 & 表单域名称3 = 值3……
要注意的是“值”必须是经过HTMLEncode的，即不能包含“ <>=& ”这些符号。

本例子要提交的数据应该是：
userid = value1 & password = value2

用C#写提交程序：
string  strId  =   " guest " ;
string  strPassword =   " 123456 " ;

ASCIIEncoding encoding = new  ASCIIEncoding();
string  postData = " userid= " + strId;
postData  +=  ( " &password= " + strPassword);

byte [] data  =  encoding.GetBytes(postData);

//  Prepare web request
HttpWebRequest myRequest  =
(HttpWebRequest)WebRequest.Create( " http://www.here.com/login.asp " );

myRequest.Method  =   " POST " ;
myRequest.ContentType = " application/x-www-form-urlencoded " ;
myRequest.ContentLength  =  data.Length;
Stream newStream = myRequest.GetRequestStream();

//  Send the data.
newStream.Write(data, 0 ,data.Length);
newStream.Close();

//  Get response
HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
StreamReader reader  =   new  StreamReader(response.GetResponseStream(),Encoding.Default);
string  content  =  reader.ReadToEnd();
Response.Write(content); 

 

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