您需要CookieCollection；在收到登录请求的响应后，您可以从响应中读取cookie.

you need the CookieCollection; after receiving the response from your login request you can read the cookies out of the response.

        var cookies = new CookieContainer();
        ServicePointManager.Expect100Continue = false;
        CookieCollection receivedCookies = new CookieCollection();

        try
        {
            var request = (HttpWebRequest) WebRequest.Create(ServerUrl + "index.php");
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.CookieContainer = cookies;

            string postData = "try=&username=someLogin&password=somepass";
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);
            request.ContentLength = byteArray.Length;

            using (Stream dataStream = request.GetRequestStream())
            {
                dataStream.Write(byteArray, 0, byteArray.Length);
            }

            // Get the response.
            using (WebResponse response = request.GetResponse())
            {
                receivedCookies = ((HttpWebResponse) response).Cookies;
                Logger.DebugFormat("received {0} cookies", receivedCookies.Count);
                using (Stream responseStream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(responseStream))
                    {
                        string responseFromServer = reader.ReadToEnd();
                        Logger.DebugFormat("response from server after login-post: {0}", responseFromServer);
                    }
                }
            }
        }
        catch (Exception ex)
        {
            Logger.FatalFormat("there was an exception during login: {0}", ex.Message);
            return (int) CreateResult.GenericError;
        }

在后续请求期间，您必须始终添加该cookie:

during sub-sequent requests you have to add always that cookie(s):

            var request =
                (HttpWebRequest)WebRequest.Create(ServerUrl + "index.php?nav=callcenter&sub=ccagents&action=new");
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.CookieContainer = cookies;
            request.CookieContainer.Add(receivedCookies);