如何在C#中复制此JavaScript

这是JavaScript

function ChangeVol(id)
{
    document.form.selectFS_devId.value = id;
    document.form.selectFS_currentNameSpace.value = "";
    document.form.submit();
}
function ChangeEvsVol(id, vNodeId)
{
    document.form.selectFS_evsId.value = vNodeId;
    document.form.selectFS_currentNameSpace.value = "";
    ChangeVol(id);
}
document.form.selectFS_devId.value = "all"  
document.form.selectFS_evsId.value = "2"

这是我使用的当前C#代码

Uri url = new Uri("https://mgr/app");
HttpWebRequest request = null;
ServicePointManager.ServerCertificateValidationCallback =
   ((sender, certificate, chain, sslPolicyErrors) => true);
CookieContainer cookieJar = new CookieContainer();
request = (HttpWebRequest)WebRequest.Create(url);
request.CookieContainer = cookieJar;
request.Method = "GET";
HttpStatusCode responseStatus;
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
     responseStatus = response.StatusCode;
     url = request.Address;
}
if (responseStatus == HttpStatusCode.OK)
{
      UriBuilder urlBuilder = new UriBuilder(url);
      urlBuilder.Path = 
          urlBuilder.Path.Remove(urlBuilder.Path.LastIndexOf('/')) + 
          "/j_security_check";
      request = (HttpWebRequest)WebRequest.Create(urlBuilder.ToString());
      request.Referer = url.ToString();
      request.CookieContainer = cookieJar;
      request.Method = "POST";
      request.ContentType = "application/x-www-form-urlencoded";
      using (Stream requestStream = request.GetRequestStream())
      using (StreamWriter requestWriter = new StreamWriter(requestStream, Encoding.ASCII))
      {
           string postData = "j_username=user&j_password=user&submit=Send";
           requestWriter.Write(postData);
      }
      string responseContent = null;
      string myTargetString = "https://mgr/app/action/storage.VivolAction/eventsubmit_dopreparevivollist/ignored/f5/true";
      using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
      using (Stream responseStream = response.GetResponseStream())
      using (StreamReader responseReader = new StreamReader(responseStream))
      {
         responseContent = responseReader.ReadToEnd();
      }
      Console.WriteLine(responseContent);
      request = (HttpWebRequest)WebRequest.Create(myTargetString);
      request.Method = "GET";
      request.CookieContainer = cookieJar;
      using (HttpWebResponse responsedownload = (HttpWebResponse)request.GetResponse())
      using (Stream responseStream = responsedownload.GetResponseStream())
      using (StreamReader responseReader = new StreamReader(responseStream))
      {
            responseContent = responseReader.ReadToEnd();
      }
      Console.WriteLine(responseContent);

问题是字符串myTargetString没有加载javascript参数，如果我能在URL中复制这些参数，那就太棒了，如果不能，我需要做什么才能像上面在StreamWriter中那样在帖子请求中提交这些参数？

using (StreamWriter requestWriter = new StreamWriter(requestStream, Encoding.ASCII))
            {
                string postData = "j_username=user&j_password=user&submit=Send";
                requestWriter.Write(postData);
            }

我在url中所说的可能是这样的：

https://mgr/app/action/storage.VivolAction/eventsubmit_dopreparevivollist/ignored?&evsId=1&devId=all&currentpagenumberbottom=1&filtername=&currentpagenumber=1&quotaactionlink=/mgr/app/action/storage.VivolQuotaAction&ascending=true&currentpagesize=20&ignoreErrorMessages=true&pageindex=1&sortby=name&filterpath=

Fiddler给我提供了这个

POST https://mgr/app/action/storage.SelectFileSystemAction/eventsubmit_doprocessselectfilesystem/ignored  
Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash,   application/xaml+xml, application/x-ms-xbap, application/x-ms-application,   application/vnd.ms-xpsdocument, application/vnd.ms-excel, application/vnd.ms-powerpoint,   application/msword, */*  
Referer: https://mgr/app/action/storage.SelectFileSystemAction  /eventsubmit_doprepareselectfilesystem/ignored  
Accept-Language: en-us  
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0)  
Content-Type: application/x-www-form-urlencoded  
Accept-Encoding: gzip, deflate  
Host: arc  
Content-Length: 378  
Connection: Keep-Alive  
Cache-Control: no-cache  
Cookie: jid=asdsad ; jsso = asdas2sa    
op=&selectFS_devId=all&selectFS_previous_template=&selectFS_evsId=2&selectFS_currentNameSpace=&selectFS_action_class=storage.VivolAction&selectFS_action_method=doPreparevivollist&selectFS_uniqueId=13655b454e3951462f&selectFS_dont_alter_current=false&selectFS_disableReplicationTargets=true&selectFS_disableReadCache=true&selectFS_disableWorm=false&selectFS_disableUnmounted=true

我可以在那里看到electFS_devId=all和selectFS_evsId=2，我需要更改EVSID，但我不知道如何构造URL。是的，我更改了cookie id的