public static async Task <Int32?> ConnectEleve(String _Email = null, String _Password = null)
        {
            var _Client = new HttpClient();

            _Client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json; charset=utf-8");


            ElevesSearchParameters _Parameters = new ElevesSearchParameters();

            _Parameters.Email    = _Email;
            _Parameters.Password = _Password;
            HttpContent _JsonRequestContent = new StringContent(_Parameters.ToSerializedJson(), Encoding.UTF8, "application/json");


            HttpRequestMessage _Request = new HttpRequestMessage
            {
                RequestUri = new Uri(Constants.WS_URL + "/Eleves/ConnectEleve"),
                Method     = HttpMethod.Post,
                Headers    = { { "APIKey", Constants.WS_PASSKEY } },
                Content    = _JsonRequestContent
            };

            HttpResponseMessage _Response = _Client.SendAsync(_Request).Result;
            String _JsonResponseContent   = await _Response.Content.ReadAsStringAsync();

            Int32?_Id = JsonConvert.DeserializeObject <Int32?>(_JsonResponseContent);

            return(_Id);
        }
        public static async Task <Eleve> GetEleve(Int32?_Id)
        {
            var _Client = new HttpClient();

            _Client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json; charset=utf-8");


            ElevesSearchParameters _Parameters = new ElevesSearchParameters();

            _Parameters.Id = _Id;
            HttpContent _JsonRequestContent = new StringContent(_Parameters.ToSerializedJson(), Encoding.UTF8, "application/json");


            HttpRequestMessage _Request = new HttpRequestMessage
            {
                RequestUri = new Uri(Constants.WS_URL + "/Eleves/GetEleves"),
                Method     = HttpMethod.Post,
                Headers    = { { "APIKey", Constants.WS_PASSKEY } },
                Content    = _JsonRequestContent
            };

            HttpResponseMessage _Response = _Client.SendAsync(_Request).Result;
            String _JsonResponseContent   = await _Response.Content.ReadAsStringAsync();

            List <Eleve> _Eleves = JsonConvert.DeserializeObject <List <Eleve> >(_JsonResponseContent);

            Eleve _Eleve = new Eleve();

            if (_Eleves.Count > 0)
            {
                _Eleve = _Eleves[0];
            }

            return(_Eleve);
        }