用WebClient方法登录一个网页，老出错

用WebClient方法登录一个网页，老出错，请指教
高手帮我测试下吧，我需要通过程序来登录网页
地址是：http://www.inang.cn/blog/login.asp
用户名：test
密码：testtest

代码如下，为什么手工可以登录，代码却登录不了
string   uriString   =   "http://www.inang.cn/blog/login.asp?act=login ";
string   postString   =   "userName=test&password=testtest&Login=Login&CookiesDay=1 ";

WebClient   webClient   =   new   WebClient();
webClient.Headers.Add( "Content-Type ",   "application/x-www-form-urlencoded ");
byte[]   postData   =   Encoding.ASCII.GetBytes(postString);
byte[]   responseData   =   webClient.UploadData(uriString,   "POST ",   postData);
string   srcString   =   Encoding.UTF8.GetString(responseData);

[解决办法]
tring url = "http://my.b2b.hc360.com/my/turbine/template/firstview,other_login.html ";

string indata = @ "LoginID=mytestcs&Passwd=aabbccdd&LoginChk=true&Submit=%B5%C7%A1%A1%A1%A1%C2%BC ";

string outdata= " ";

CookieContainer myCookieContainer=new CookieContainer();
//新建一个CookieContainer来存放Cookie集合
HttpWebRequest myHttpWebRequest=(HttpWebRequest)WebRequest.Create(url);
//新建一个HttpWebRequest
myHttpWebRequest.ContentType= "application/x-www-form-urlencoded ";
myHttpWebRequest.ContentLength=indata.Length;
myHttpWebRequest.Method= "POST ";
myHttpWebRequest.CookieContainer=myCookieContainer;
//设置HttpWebRequest的CookieContainer为刚才建立的那个myCookieContainer
Stream myRequestStream=myHttpWebRequest.GetRequestStream();
StreamWriter myStreamWriter=new StreamWriter(myRequestStream,Encoding.GetEncoding( "gb2312 "));
myStreamWriter.Write(indata);
//把数据写入HttpWebRequest的Request流
myStreamWriter.Close();
myRequestStream.Close();

//关闭打开对象
HttpWebResponse myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();
//新建一个HttpWebResponse
myHttpWebResponse.Cookies=myCookieContainer.GetCookies(myHttpWebRequest.RequestUri);
//获取一个包含url的Cookie集合的CookieCollection
Stream myResponseStream=myHttpWebResponse.GetResponseStream();
StreamReader myStreamReader=new StreamReader(myResponseStream,Encoding.GetEncoding( "gb2312 "));
outdata=myStreamReader.ReadToEnd();
//把数据从HttpWebResponse的Response流中读出
myStreamReader.Close();
myResponseStream.Close();
Console.WriteLine(outdata);
//显示 "登录 "

//拿到了Cookie，再进行请求就能直接读取到登录后的内容了
myHttpWebRequest=(HttpWebRequest)WebRequest.Create(url);
myHttpWebRequest.CookieContainer=myCookieContainer;//*
//刚才那个CookieContainer已经存有了Cookie,把它附加到HttpWebRequest中则能直接通过验证
myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();
myHttpWebResponse.Cookies=myCookieContainer.GetCookies(myHttpWebRequest.RequestUri);
myResponseStream=myHttpWebResponse.GetResponseStream();
myStreamReader=new StreamReader(myResponseStream,Encoding.GetEncoding( "gb2312 "));
outdata=myStreamReader.ReadToEnd();
myStreamReader.Close();
myResponseStream.Close();
Console.WriteLine(outdata);