网页抓取数据时，怎么过登陆验证？ 求大神指点

while (resultType)            {                string result = string.Empty;                string url = "http://search.zhenai.com/search/getfastmdata.jsps?gender=1&agebegin=25&ageend=35&workcityprovince=" + txtCityCode.Text + "&workcitycity=-1&Marriage=-1&Salary=-1&Education=-1&h1=-1&h2=-1&photo=1&currentpage=" + pageIndex;                HttpWebRequest hwr = (HttpWebRequest)HttpWebRequest.Create(url);                hwr.Method = "GET";                hwr.Referer = "localhost";                using (WebResponse wr = hwr.GetResponse())                {                    StreamReader sr = new StreamReader(wr.GetResponseStream(), Encoding.Default);                    result = sr.ReadToEnd();                    wr.Close();                }                if (result.Contains(errorstr))                {                    resultType = false;                    pageIndex = 1;                    lblsuccess.Text = "当前城市数据采集完毕!";                    MessageBox.Show("当前城市数据采集完毕!");                }                else                {                    //抓取数据代码                }             }