无法从ASP获取HTTP发布内容.网的网站

我正在尝试从ASP下载文本文件内容。网的网站。在Stack-overflow和其他网站的帮助下，我可以登录网站并获得认证。然而，我的第二个帖子请求是下载一个文本文件，它只是返回我的文本文件的头，这是管道(|)分隔。我非常接近完成这个任务，只有专家的意见可以让我通过这个简单的看似困难的任务超过一天了。下面是完整的代码。如果有人能让我知道我可以在哪里添加一些东西，使技巧工作。

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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;
using System.Security.Cryptography.X509Certificates;
using System.Net.Security;
using System.Collections.Specialized;
using System.Web;
namespace Login_Test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            SSLValidator.OverrideValidation();
            CookieContainer cookies = new CookieContainer();
            HttpWebRequest request1 = (HttpWebRequest)WebRequest.Create("https://www.abcd.org/");
            request1.CookieContainer = cookies;
            request1.Method = "GET";           
            request1.KeepAlive = false;            
             //Get the response from the server and save the cookies from the first request..
            HttpWebResponse response1 = (HttpWebResponse)request1.GetResponse();            
            System.IO.Stream responseStream = response1.GetResponseStream();
            System.IO.StreamReader reader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
            string srcString = reader.ReadToEnd();
            // get the page ViewState                
            string viewStateFlag = "id='"__VIEWSTATE'" value='"";
            int i = srcString.IndexOf(viewStateFlag) + viewStateFlag.Length;
            int j = srcString.IndexOf("'"", i);
            string viewState = srcString.Substring(i, j - i);
            // get page EventTarget                
            string eventTargetFlag = "id='"__EVENTTARGET'" value='"";
            i = srcString.IndexOf(eventTargetFlag) + eventTargetFlag.Length;
            j = srcString.IndexOf("'"", i);
            string eventTarget = srcString.Substring(i, j - i);
            // get page EventArgument                
            string eventArgumentFlag = "id='"__EVENTARGUMENT'" value='"";
            i = srcString.IndexOf(eventArgumentFlag) + eventArgumentFlag.Length;
            j = srcString.IndexOf("'"", i);
            string eventArgument = srcString.Substring(i, j - i);
            // get page manScript_HiddenFieldFlag                
            string manScript_HiddenFieldFlag = "id='"manScript_HiddenField'" value='"";
            i = srcString.IndexOf(manScript_HiddenFieldFlag) + manScript_HiddenFieldFlag.Length;
            j = srcString.IndexOf("'"", i);
            string Script_HiddenField = srcString.Substring(i, j - i);
            string submitButton = "";
            string lang = "";
            string usr1 = "";
            string pwd1 = "";
            // UserName and Password
            string userName = "username";
            string password = "password";
            // Convert the text into the url encoding string
            viewState = System.Web.HttpUtility.UrlEncode(viewState);
            eventTarget = System.Web.HttpUtility.UrlEncode("");
            eventArgument = System.Web.HttpUtility.UrlEncode("");
            lang = System.Web.HttpUtility.UrlEncode("en-US");
            submitButton = System.Web.HttpUtility.UrlEncode(submitButton);
            usr1 = System.Web.HttpUtility.UrlEncode(usr1);
            pwd1 = System.Web.HttpUtility.UrlEncode(pwd1);
            // Concat the string data which will be submit
            string formatString =
                     "Script_HiddenField={0}&__EVENTTARGET={1}&__EVENTARGUMENT={2}&__VIEWSTATE={3}&lng={4}&p$lt$TopRightZone$Login1$UserName={5}&p$lt$TopRightZone$Login1$Password={6}&p$lt$TopRightZone$Login1$btnLogon={7}&p$lt$MainZone$pageplaceholder$p$lt$MainZone$Login1$UserName={8}&p$lt$MainZone$pageplaceholder$p$lt$MainZone$Login1$Password={9}";
            string postString =
                     string.Format(formatString, Script_HiddenField, eventTarget, eventArgument, viewState, lang, userName, password, submitButton, usr1, pwd1);
            //Send the request to login to the ASP.NET website           
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.abcd.org/");            
            request.CookieContainer = cookies;            
            var data = Encoding.ASCII.GetBytes(postString.ToString());            
            request.Method = "POST";
            request.KeepAlive = false;
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = data.Length;
            request.ProtocolVersion = HttpVersion.Version10;
            request.AllowAutoRedirect = true;           
            request.Headers.Add("Accept-Encoding", "gzip, deflate");
            using (var stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }
            var response = (HttpWebResponse)request.GetResponse();
            var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
            viewStateFlag = "id='"__VIEWSTATE'" value='"";
            i = responseString.IndexOf(viewStateFlag) + viewStateFlag.Length;
            j = responseString.IndexOf("'"", i);
            viewState = responseString.Substring(i, j - i);
            // Concat the string data which will be submit
            formatString =
                     "Script_HiddenField={0}&__EVENTTARGET={1}&__EVENTARGUMENT={2}&__VIEWSTATE={3}&lng={4}&p$lt$TopRightZone$ux$Download={5}";
            postString =
                     string.Format(formatString, "", "", "", System.Web.HttpUtility.UrlEncode(viewState), System.Web.HttpUtility.UrlEncode("en-US"), System.Web.HttpUtility.UrlEncode("1"));
            // Send request2 to download the text file            
            HttpWebRequest request2 = (HttpWebRequest)WebRequest.Create("https://www.abcd.org/download?t=1&c=123456");
            request.CookieContainer = cookies;
            data = Encoding.ASCII.GetBytes(postString.ToString());
            request2.Method = "POST";
            request2.KeepAlive = false;
            request2.ContentType = "application/x-www-form-urlencoded";
            request2.ContentLength = data.Length;
            request2.ProtocolVersion = HttpVersion.Version10;
            request2.AllowAutoRedirect = true;
            request2.Headers.Add("Accept-Encoding", "gzip, deflate");
            using (var stream = request2.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }
            var response2 = (HttpWebResponse)request2.GetResponse();
            var responseString2 = new StreamReader(response2.GetResponseStream()).ReadToEnd();
        }
    }
    public static class SSLValidator
    {
        private static bool OnValidateCertificate(object sender, X509Certificate certificate, X509Chain chain,
                                                  SslPolicyErrors sslPolicyErrors)
        {
            return true;
        }
        public static void OverrideValidation()
        {
            ServicePointManager.ServerCertificateValidationCallback =
                OnValidateCertificate;
            ServicePointManager.Expect100Continue = true;
        }
    }
}