HttpWebRequest和HttpWebResponse的应用

public class Httpparam
    {
        public string UserAgent { get; set; }
        public string Accept { get; set; }
        public string ContentType { get; set; }
        public string Referer { get; set; }
    }

    public class HttpHelper
    {
        //下载源码
        public static string GetString(string url, Httpparam para, Encoding encoding)
        {
            var res = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
            res.ContentType = para.ContentType;
            res.Accept = para.Accept;
            res.UserAgent = para.UserAgent;
            res.Referer = para.Referer;
            var stream = new StreamReader(res.GetResponse().GetResponseStream(), encoding);
            var result=stream.ReadToEnd();
            stream.Close();
            stream.Dispose();
            res.Abort();
            return result;
        }
        //上传数据
        public static string PostData(string url, Httpparam para, Encoding encoding,string data)
        {
            var buf = encoding.GetBytes(data);

            var res = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
            res.Method = "post";
            res.ContentType = para.ContentType;
            res.Accept = para.Accept;
            res.UserAgent = para.UserAgent;
            res.Referer = para.Referer;

            var reqstream = res.GetRequestStream();
            reqstream.Write(buf, 0, buf.Length);
            reqstream.Close();
            reqstream.Dispose();

            var stream = new StreamReader(res.GetResponse().GetResponseStream(), encoding);
            var result = stream.ReadToEnd();
            stream.Close();
            stream.Dispose();
            res.Abort();
            return result;
        }
    }