Custom Events in Xamarin Page c#

Question

I currently am facing the following issue:

I am trying to fire an event when a user entered valid credentials so that I can switch page and so on.

The Issue is I am unable to hook into the event for some reason (altho I'm pretty sure it will be something stupid).

The Class firing the event:

namespace B2B
{

    public partial class LoginPage : ContentPage
    {
        public event EventHandler OnAuthenticated;

        public LoginPage ()
        {
            InitializeComponent ();
        }

        void onLogInClicked (object sender, EventArgs e)
        {
            loginActivity.IsRunning = true;

            errorLabel.Text = "";

            RestClient client = new RestClient ("http://url.be/api/");

            var request = new RestRequest ("api/login_check",  Method.POST);
            request.AddParameter("_username", usernameText.Text);
            request.AddParameter("_password", passwordText.Text);

            client.ExecuteAsync<Account>(request, response => {

                Device.BeginInvokeOnMainThread ( () => {
                    loginActivity.IsRunning = false;

                    if(response.StatusCode == HttpStatusCode.OK)
                    {
                        if(OnAuthenticated != null)
                        {
                            OnAuthenticated(this, new EventArgs());
                        }
                    }
                    else if(response.StatusCode == HttpStatusCode.Unauthorized)
                    {
                        errorLabel.Text = "Invalid Credentials";
                    }
                });

            });

        }
    }
}

And in the 'main class'

namespace B2B
{
    public class App : Application
    {
        public App ()
        {
            // The root page of your application
            MainPage = new LoginPage();

            MainPage.OnAuthenticated += new EventHandler (Authenticated);

        }

        static void Authenticated(object source, EventArgs e) {
            Console.WriteLine("Authed");
        }
    }
}

When I try to build the application I get:

Type 'Xamarin.Forms.Page' does not containt a definition for 'OnAuthenticated' and no extension method OnAuthenticated

I've tried adding a delegate inside the LoginPage class, outside of it but it doesn't help.

Could anyone be so kind to point me out what stupid mistake I am making ?

Answer 1

MainPage is defined as Xamarin.Forms.Page. This class has no property called OnAuthenticated. Hence the error. You need to store the instance of LoginPage in a variable of that type before assigning it to MainPage in order to have access to the properties and methods defined in that class:

var loginPage = new LoginPage();
loginPage.OnAuthenticated += new EventHandler(Authenticated); 
MainPage = loginPage;