C# WinForm调用Webservice接口的POST方法实现

namespace FleaMarket//ÃüÃû¿Õ¼ä  
{  
    class HttpUtils  
    {  
        public static string Post(string Url, System.Collections.Hashtable pars)  
        {  
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);  
            request.Method = "POST";  
            request.ContentType = "application/x-www-form-urlencoded";  
  
            string buffer = "";  
            if (!(pars == null || pars.Count == 0))  
            {  
  
                foreach (string key in pars.Keys)  
                {  
                    buffer = buffer + "&" + key + "=" + pars[key].ToString();  
                }  
            }  
  
  
            byte[] postmsg = Encoding.UTF8.GetBytes(buffer);  
  
            Stream myResponseStream = request.GetRequestStream();  
            myResponseStream.Write(postmsg, 0, postmsg.Length);  
  
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();  
            StreamReader myStreamReader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);  
            string retString = myStreamReader.ReadToEnd();