RegisterPage.xaml.cs

using Coursework1.Tables;
using SQLite;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace Coursework1.Views
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class RegisterPage : ContentPage
    {
        public RegisterPage()
        {
            InitializeComponent();
        }

        void Button_Clicked(object sender, EventArgs e)
        {
            var dbpath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "UserDatabase.db");
            var db = new SQLiteConnection(dbpath);
            db.CreateTable<RegisteredUsers>();

            var item = new RegisteredUsers()
            {
                Username = EntryUsername.Text,
                Password = EntryPassword.Text,
                Email = EntryEmail.Text
            };
            db.Insert(item);

            if (EntryUsername.Text.Equals(null) || EntryPassword.Text.Equals(null) || EntryEmail.Text.Equals(null))
            {
                Device.BeginInvokeOnMainThread(async () =>
                {
                    var output = await this.DisplayAlert("Please fill all the fields", "Registration failed", "Okay", "Cancel");
                    if (output)
                        await Navigation.PushModalAsync(new RegisterPage());
                });
            }
            else
            {

                Device.BeginInvokeOnMainThread(async () =>
                {
                    var result = await this.DisplayAlert("Registration Succesful", "Press okay to go to log in page", "Okay", "Cancel");
                    if (result)
                        await Navigation.PushModalAsync(new LogInPage());
                });

            }



        }
        void Button_Clicked_1(object sender, EventArgs e)
        {
            App.Current.MainPage = new NavigationPage(new LogInPage());
        }
    }
}