public static string PostMoths(string url, string param)
        {
            string strURL = url;
            System.Net.HttpWebRequest request;
            request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
            request.Method = "POST";
            request.ContentType = "application/json;charset=UTF-8";
            string paraUrlCoded = param;
            byte[] payload;
            payload = System.Text.Encoding.UTF8.GetBytes(paraUrlCoded);
            request.ContentLength = payload.Length;
            Stream writer = request.GetRequestStream();
            writer.Write(payload, 0, payload.Length);
            writer.Close();
            System.Net.HttpWebResponse response;
            response = (System.Net.HttpWebResponse)request.GetResponse();
            System.IO.Stream s;
            s = response.GetResponseStream();
            string StrDate = "";
            string strValue = "";
            StreamReader Reader = new StreamReader(s, Encoding.UTF8);
            while ((StrDate = Reader.ReadLine()) != null)
            {
                strValue += StrDate + "\r\n";
            }
            return strValue;
        }

string test = “Testing 1-2-3″;

// convert string to stream
MemoryStream stream = new MemoryStream();
StreamWriter writer = new StreamWriter( stream );
writer.Write( test );
writer.Flush();

// convert stream to string
stream.Position = 0;
StreamReader reader = new StreamReader( stream );
string text = reader.ReadToEnd();