自动登录获取网页源码 500错误!
private   void   btnDownload_Click(object   sender,   System.EventArgs   e)
{
string   strResult;

if   (HttpContext.Current.Application[ "cookieheader "]   !=   null)
{
cookieheader   =   (string)HttpContext.Current.Application[ "cookieheader "];
}
else
{
//Login   into   the   website   and   keep   the   cookie   for   the   session   in   the   application   variable
string   strLogin   =   Login( "https://https-sec.xfab.com/fo/logon.do ",   "username=username&password=password ")   ;
}


strResult   =   getPage( "https://https-sec.xfab.com/fo/downloadstaticreport.do ",   "id=0 ")   ;
}

public   static   string   getPage(String   url,   String   paramList)  
{
HttpWebResponse   res   =   null;
string   strResult   =   " ";
try  
{
HttpWebRequest   req   =   (HttpWebRequest)WebRequest.Create(url);
req.Method   =   "POST ";
req.KeepAlive   =   true;
req.ContentType   =   "application/x-www-form-urlencoded ";
CookieContainer   cookieCon   =   new   CookieContainer();
req.CookieContainer   =   cookieCon;
req.CookieContainer.SetCookies(new   Uri(url),cookieheader);
StringBuilder   UrlEncoded   =   new   StringBuilder();
Char[]   reserved   =   { '? ',   '= ',   '& '};
byte[]   SomeBytes   =   null;

if   (paramList   !=   null)  
{
int   i=0,   j;
while(i <paramList.Length)
{
j=paramList.IndexOfAny(reserved,   i);
if   (j==-1)
{
UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i,   paramList.Length-i)));
break;
}
UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i,   j-i)));
UrlEncoded.Append(paramList.Substring(j,1));
i   =   j+1;
}
SomeBytes   =   Encoding.UTF8.GetBytes(UrlEncoded.ToString());
req.ContentLength   =   SomeBytes.Length;
Stream   newStream   =   req.GetRequestStream();
newStream.Write(SomeBytes,   0,   SomeBytes.Length);
newStream.Close();
}  
else  
{
req.ContentLength   =   0;
}


res   =   (HttpWebResponse)req.GetResponse();
Stream   ReceiveStream   =   res.GetResponseStream();
Encoding   encode   =   System.Text.Encoding.GetEncoding( "utf-8 ");
StreamReader   sr   =   new   StreamReader(   ReceiveStream,   encode   );
Char[]   read   =   new   Char[256];
int   count   =   sr.Read(   read,   0,   256   );
while   (count   >   0)  
{
String   str   =   new   String(read,   0,   count);
strResult   +=   str;
count   =   sr.Read(read,   0,   256);
}
}  
catch(Exception   e)  
{
strResult   =   e.ToString();