c# httprequest

// Global cookies Collection
CookieCollection cookies = new CookieCollection();

// Get ile Veri alma Fonksiyonu
public string VeriOku(string url)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            HttpWebResponse response = null;
            request.CookieContainer = new CookieContainer();
            request.CookieContainer.Add(cookies);
            request.Credentials = CredentialCache.DefaultCredentials;
            try
            {
                response = (HttpWebResponse)request.GetResponse();
                cookies = response.Cookies;
            }
            catch (WebException ex)
            {
                return "hata";
            }
            Stream dataStream = response.GetResponseStream();
            StreamReader reader = new StreamReader(dataStream);
            string responseFromServer = reader.ReadToEnd();
            reader.Close();
            response.Close();
            return responseFromServer;
   }
//POST veri Gönderme Fonksiyonu
    public string VeriGonder(string url, string postData)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Method = "POST";
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);
            request.CookieContainer = new CookieContainer();
            request.CookieContainer.Add(cookies);
            ((HttpWebRequest)request).UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Firefox/38.0";
            request.ContentLength = byteArray.Length;
            System.IO.Stream dataStream = request.GetRequestStream();
            dataStream.Write(byteArray, 0, byteArray.Length);
            dataStream.Close();
            HttpWebResponse response = null;
            try
            {
                response = (HttpWebResponse)request.GetResponse();
            }
            catch (WebException ex)
            {
                return "hata";
            }
            dataStream = response.GetResponseStream();
            System.IO.StreamReader reader = new System.IO.StreamReader(dataStream);
            string responseFromServer = reader.ReadToEnd();
            reader.Close();
            dataStream.Close();
            response.Close();
            return responseFromServer;
        }