file.cs

    public sealed partial class MainPage : Page {

        CoreDispatcher dispatcher = CoreWindow.GetForCurrentThread().Dispatcher;

        DiscordSocketClient _client;

        string token = "";

        public MainPage() {
            this.InitializeComponent();

            _client = new DiscordSocketClient();

            SetupEventHandlers();

            ConnectAndLogin();
        }

        private void SetupEventHandlers() {
            _client.MessageReceived += async (message) => {
                await AppendText(message.Content);
                //return null;
            };

            _client.Connected += async () => {
                await AppendText("Connected.");

                var guilds = await _client.GetGuildsAsync();

                try {
                    foreach (var guild in guilds) {
                        await AppendText(guild.Name + " -- " + guild.Id);
                    }
                } catch (Exception ex) {
                    await AppendText(ex.Message);
                }

                await AppendText("Guild list complete.");
            };
        }

        private async Task ConnectAndLogin() {
            textBlock.Text = "Running.\n";

            await _client.LoginAsync(TokenType.User, token, true);
            await _client.ConnectAsync();
        }

        private async Task AppendText(string text) {
            await dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => {
                textBlock.Text += text + "\n";
            });
        }
        
    }