post传输数据给指定的url并返回值

private string PostData(string serverName,string postData)
    {
        postData = "body="+postData;
        UTF8Encoding encoding = new UTF8Encoding();
        byte[] data = encoding.GetBytes(postData);
        string realUrl = url + "service=" + serverName;
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(realUrl);
        myRequest.Method = "POST";
        myRequest.ContentType = "application/x-www-form-urlencoded";
        myRequest.ContentLength = data.Length;
        Stream newStream = myRequest.GetRequestStream();
        newStream.Write(data, 0, data.Length);
        newStream.Close();
        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
        string content = reader.ReadToEnd();
        reader.Close();
        return content;
    }