public static string GetUrltoHtml(string Url,string type)
        {
            try
            {
                System.Net.WebRequest wReq = System.Net.WebRequest.Create(Url);
                // Get the response instance.
                System.Net.WebResponse wResp = wReq.GetResponse();
                System.IO.Stream respStream = wResp.GetResponseStream();
                // Dim reader As StreamReader = New StreamReader(respStream)
                using (System.IO.StreamReader reader = new System.IO.StreamReader(respStream, Encoding.GetEncoding(type)))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (System.Exception ex)
            {
                //errorMsg = ex.Message;
            }
            return "";
        }

///<summary>
///采用https协议访问网络
///</summary>
///<param name="URL">url地址</param>
///<param name="strPostdata">发送的数据</param>
///<returns></returns>
public string OpenReadWithHttps(string URL, string strPostdata, string strEncoding)
{
    Encoding encoding = Encoding.Default;
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
    request.Method = "post";
    request.Accept = "text/html, application/xhtml+xml, */*";
    request.ContentType = "application/x-www-form-urlencoded";
    byte[] buffer = encoding.GetBytes(strPostdata);
    request.ContentLength = buffer.Length;
    request.GetRequestStream().Write(buffer, 0, buffer.Length);
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    using( StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding(strEncoding)))
      {
           return reader.ReadToEnd();
      }
}