ASP.Net MVC自动登录外部站点

Question

我有一个MVC站点（ASP.Net），我希望能够使用SSO自动登录到另一个站点。该网站使用Javascript进行身份验证，我有一个基本的PHP网站，看起来像这样，它的效果很好。

<form name="nechoSSO" action="https://expense.cybershift.net/NE7P022ExpenseWeb/CarouselProdne7sso.jsp" method="post" >
<input type="HIDDEN" name="userid" value="<? echo $username; ?>">
<input type="HIDDEN" name="password" value="password" >

我现在用MVC做同样的事情，但自动重定向和登录。我怎么能这样做呢？

我尝试使用HttpWebRequest，但我无法让它重定向。

string formUrl = "https://expense.cybershift.net/NE7P022ExpenseWeb/CarouselProdne7sso.jsp";
string dataToPOST = "username=testUser&password=password";

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(formUrl);
request.KeepAlive = true;
request.Method = "POST";
// Turn off AutoRedirection
request.AllowAutoRedirect = true;

// Split Form data into bytes
byte[] dataToBytes = Encoding.ASCII.GetBytes(dataToPOST);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = dataToBytes.Length;

// Write Data to Stream for posting
using (Stream requestStream = request.GetRequestStream())
{
    requestStream.Write(dataToBytes, 0, dataToBytes.Length);
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
}