Send C# variables to PHP via POST
public static string Post(string service, IDictionary<string, string> objects)
    {
        // Create a request using a URL that can receive a post.
        WebRequest request = WebRequest.Create(ServiceAdress+service+".php");
        // Set the Method property of the request to POST.
        request.Method = "POST";
        // Create POST data and convert it to a byte array.

        StringBuilder b= new StringBuilder();
        foreach(KeyValuePair<string,string>  o in objects)
            b.Append(HttpUtility.UrlEncode(o.Key)).Append("=").Append(HttpUtility.UrlEncode(o.Value??"")).Append("&");
        if (PHPSESSID != null)
            b.Append("PHPSESSID=").Append(PHPSESSID).Append('&');

        string postData = b.ToString(0, b.Length - 1);
        byte[] byteArray = Encoding.UTF8.GetBytes(postData);
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = byteArray.Length;
        Stream dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);
        dataStream.Close();
        WebResponse response = request.GetResponse();

        if (((HttpWebResponse)response).StatusCode != HttpStatusCode.OK)
            return null;

        dataStream = response.GetResponseStream();
        StreamReader reader = new StreamReader(dataStream);
        string responseFromServer = reader.ReadToEnd();
        Console.WriteLine(responseFromServer);
        reader.Close();

        dataStream.Close();
        response.Close();
        return responseFromServer;
    }