client = new HttpClient();
client.DefaultRequestHeaders.Add("User-Agent", "RingtoneApplication");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
Object[] dataObj = CreateData();
string dataString = JsonConvert.SerializeObject(dataObj);
var values = new List<KeyValuePair<string, string>>();
values.Add(new KeyValuePair<string, string>("data", dataString));
values.Add(new KeyValuePair<string, string>("method", "getRintoneCategories"));
string token = CreateToken(dataString, "123");
values.Add(new KeyValuePair<string, string>("token", token));
var content = new FormUrlEncodedContent(values);
var response = await client.PostAsync("http://192.168.0.103/new_ringtone/", content);
responseString = await response.Content.ReadAsStringAsync();