HttpRequest和Response无法在Aspx页面上运行

Question

我使用fiddler并且所有参数，变量，formfeild，cookies等都与使用浏览器相同。遗憾的是，重定向到结果页面时似乎丢失了这些值。

    protected string WebURL = @"https://webapps.mvd.newmexico.gov/ONLINEDLRENEWAL/Default.aspx"; 


    protected void Button1_Click(object sender, EventArgs e)
    { 
        // first, request the login form to get the viewstate value
        //HttpWebRequest webRequest = WebRequest.Create(WebURL) as HttpWebRequest;

        ////    HttpWebResponse resp = (HttpWebResponse)webRequest.GetResponse();
        //StreamReader responseReader = new StreamReader(
        //  resp.GetResponseStream()
        //   );

        CookieContainer cookieContainer = new CookieContainer();
        HttpWebRequest webRequest = WebRequest.Create(WebURL) as HttpWebRequest;
        webRequest.CookieContainer = cookieContainer;

            StreamReader responseReader = new StreamReader(
                  webRequest.GetResponse().GetResponseStream()
               );

            string responseData = responseReader.ReadToEnd();
            responseReader.Close();

        // extract the viewstate value and build out POST data
        string viewState = ExtractFormField(responseData, "__VIEWSTATE");
        string EVENTTARGET = ExtractFormField(responseData, "__EVENTTARGET");
        string EVENTARGUMENT = ExtractFormField(responseData, "__EVENTARGUMENT");
        string VIEWSTATEENCRYPTED = ExtractFormField(responseData, "__VIEWSTATEENCRYPTED");
        string EVENTVALIDATION = ExtractFormField(responseData, "__EVENTVALIDATION");
        string ToolkitScriptManager1 = ExtractFormField(responseData, "MainContent_ToolkitScriptManager1_HiddenField");
        string postData = "";

        postData = "MainContent_ToolkitScriptManager1_HiddenField=" + ";;AjaxControlToolkit, Version=4.1.60919.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e:en-US:ee051b62-9cd6-49a5-87bb-93c07bc43d63:5546a2b:475a4ef5:effe2a26:2a35a54f:4355a41:3ac3e789"; // ToolkitScriptManager1;
        postData += "&__EVENTTARGET=" + EVENTTARGET;
        postData += "&__EVENTARGUMENT=" + EVENTARGUMENT;
        postData += "&__VIEWSTATE=" + viewState; 

        postData += "&__EVENTVALIDATION=" + EVENTVALIDATION;  
        postData += "&ctl00$MainContent$txtDLNo=999999999";
        postData += "&ctl00$MainContent$MaskedEditExtender1_ClientState=";
        postData += "&ctl00$MainContent$txtDOB=11/24/1987";
        postData += "&ctl00$MainContent$MaskedEditExtender5_ClientState=";
        postData += "&ctl00$MainContent$txtLast4OfSSN=9999";
        postData += "&ctl00$MainContent$btnSearch=Renew My License/ID";

        // now post to the login form
        webRequest = WebRequest.Create(WebURL) as HttpWebRequest;
        webRequest.Method = "POST";
        webRequest.ContentType = "application/x-www-form-urlencoded";

        webRequest.CookieContainer = cookieContainer; // cookies;
        webRequest.AllowAutoRedirect = true;
        // write the form values into the request message
        StreamWriter requestWriter = new StreamWriter(webRequest.GetRequestStream());
        requestWriter.Write(postData);
        requestWriter.Close();


        // we don't need the contents of the response, just the cookie it issues 
         responseReader = new StreamReader(
              webRequest.GetResponse().GetResponseStream()
           );
          responseData = responseReader.ReadToEnd();


        // now we can send out cookie along with a request for the protected page
        webRequest = WebRequest.Create(WebURL) as HttpWebRequest;
        webRequest.CookieContainer = cookieContainer;


        responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream());

        // and read the response
        responseData = responseReader.ReadToEnd();
        responseReader.Close();


        litResponse.Text += responseData.Replace("<", "&lt;").Replace(">", "&gt;");

        //Response.Write(responseData);      
    }