C# WCS Problem

<?php 
require_once('global.php');
use wcf\data\user\User;
$json = null;
$code = 0;
checkPassword($_POST['Username'], $_POST['Password']);
function checkPassword($username, $password) {
	if (empty($username)) {
		global $code;
		$code = 2;
		return null;
	} elseif (empty($password)) {
		global $code;
		$code = 2;
		return null;
	}
	$user = User::getUserByUsername($username);
	if (!$user->checkPassword($password)) { 
		global $code;
		$code = 32;
		return null;
	}
	else {
		global $code;
		global $json;
		$code = 1;
		$json = ["StatusCode" => $code, "UserData" =>  ["userID" => $user->userID, "username" => $user->username, "banned" => (bool)$user->banned, "banReason" => $user->banReason, "activityPoints" => $user->activityPoints, "likesReceived" => $user->likesReceived]];
		return null;
	}
}
if($code != 1)
{
	echo json_encode(["StatusCode" => $code, "UserData" => []]);
}
else
{
	echo json_encode($json);
}


?>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;
using WBBLogin.ServerData;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;


namespace WBBLogin
{


    public class LoginCompletedEventArgs : EventArgs
    {
        public readonly LoginResponse Response;


        public LoginCompletedEventArgs(LoginResponse e)
        {
            Response = e;
        }
    }


    public static class Login
    {
        public delegate void LoginCompletedHandler(LoginCompletedEventArgs e);


        public static event LoginCompletedHandler LoginCompleted;


        public static void PerformLoginAsync(Uri URL, string Username, string Password)
        {
            string PostData = String.Format("Username={0}&Password={1}", Username, Password);
            using (WebClient wc = new WebClient())
            {
                wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
                wc.UploadStringCompleted += OnLoginCompleted;
                wc.UploadStringAsync(URL, PostData);
            }


        }


        private static void OnLoginCompleted(object sender, UploadStringCompletedEventArgs e)
        {
            LoginCompletedHandler loginCompleted = LoginCompleted;
            if(loginCompleted != null)
            {
                loginCompleted(new LoginCompletedEventArgs(JsonConvert.DeserializeObject<LoginResponse>(e.Result)));
            }
        }


        public static Task<LoginResponse> PerformLoginTaskAsync(Uri address, string username, string password)
        {
            return Task.Run(delegate
            {
                var wc = new WebClient();


                string response = wc.UploadString(address, String.Format("Username={0}&Password={1}", username, password));


                return JsonConvert.DeserializeObject<LoginResponse>(response);
            });
        }
    }
}

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace WBBLogin.ServerData
{


    public enum StatusCode
    {
        Success = 1,
        DataMissing = 2,
        WrongPassword = 32
    }


    public class UserData
    {
        [JsonProperty("userID")]
        public int userID { get; set; }
        [JsonProperty("username")]
        public string username { get; set; }
        [JsonProperty("banned")]
        public bool banned { get; set; }
        [JsonProperty("banReason")]
        public string banReason { get; set; }
        [JsonProperty("activityPoints")]
        public int activityPoints { get; set; }
        [JsonProperty("likesReceived")]
        public int likesReceived { get; set; }
    }


    public class LoginResponse
    {
        public int StatusCode { get; set; }
        public UserData UserData { get; set; }
    }
}