public class Register_person: INotifyPropertyChanged

public event PropertyChangedEventHandler PropertyChanged;
public string _username;
public string _email;
[AutoIncrement,PrimaryKey]
public int Id { get; set; }

public string UserName { get
    {
        return _username;
    } set {

        _username = value;
        NotifyPropertyChanged();

    } }
public string Password { get; set; }
public string ConfirmPassword { get; set; }
public string Email { get {
        return _email;
    } set {
        _email = value;
        NotifyPropertyChanged();

    } }

public Register_person()
{

}

public class Database

public Database()
{
    Conn= DependencyService.Get<ISQLite>().GetConnection();
   Conn.CreateTable<Register_person>();

}
public void AddUsers(Register_person users)
{
    Conn.Insert(users);
}
public IEnumerable<Register_person> Getdata()
{
    return (from t in Conn.Table<Register_person>() select t).ToList();
}
public Register_person GetEmail(string mail)
{
    return Conn.Table<Register_person>().FirstOrDefault(t => t.Email == mail);
}
public Register_person GetUsername(string mail1)
{
    return Conn.Table<Register_person>().FirstOrDefault(t => t.UserName == mail1);
}

private void Login_Clicked(object sender, EventArgs e)
{
    try
    {
        db2 = new Database();
        var data = db2.Getdata();
        var data1 = data.Where(x => x.UserName == Username.Text && x.Password == Password.Text).FirstOrDefault();

        if (data1.UserName == Username.Text && data1.Password == Password.Text)
        {
            Navigation.PushAsync(new Homepage());
        }



    }
    catch (Exception ex)
    {

        if (string.IsNullOrWhiteSpace(Username.Text) || string.IsNullOrWhiteSpace(Password.Text))
        {
            userlabel.IsVisible = false;
            passwordlabel.IsVisible = false;
            userlabel1.IsVisible = true;
            passwordlabel1.IsVisible = true;

        }
        else
        {
            userlabel1.IsVisible = false;
            passwordlabel1.IsVisible = false;
            userlabel.IsVisible = true;
            passwordlabel.IsVisible = true;
            Password.Text = "";
            Forgetpasswordlabel.IsVisible = true;
        }
    }
}

private async void Registerbutton_Clicked(object sender, EventArgs e)
{
    users = new Register_person();
    db1 = new Database();
    useUsername = Username.Text;
    useEmail = REmailEntry.Text;
    var data1 = db1.GetUsername(useUsername);
    var data = db1.GetEmail(useEmail);
    var passwor = RpasswordEntry.Text;
    var passwordRegex = @"^(?=.*[A-Za-z])(?=.*d)(?=.*[$@$!%*#?&])[A-Za-zd$@$!%*#?&]{8,}$";
    var email = REmailEntry.Text;
    var emailPattern = @"^([a-zA-Z0-9_-.]+)@([a-zA-Z0-9_-.]+).([a-zA-Z]{2,5})$";


    if (data == null)
    {
        REmail3.IsVisible = false;
        if (data1 == null)
        {
            Rusername.IsVisible = false;

            if (string.IsNullOrWhiteSpace(Username.Text) && string.IsNullOrWhiteSpace(RpasswordEntry.Text) && string.IsNullOrWhiteSpace(RcpasswordEntry.Text) && string.IsNullOrWhiteSpace(REmailEntry.Text))
            {
               await DisplayAlert("Message", "Please Fill all the fields", "ok", "cancel");
            }
            else if (string.IsNullOrWhiteSpace(Username.Text))
            {
                Rusername2.IsVisible = true;
            }
            else if (string.IsNullOrWhiteSpace(RpasswordEntry.Text))
            {
                Rpassword2.IsVisible = true;
                RcpasswordEntry.Text = "";
            }
            else if (string.IsNullOrWhiteSpace(RcpasswordEntry.Text))
            {
                RCpassword2.IsVisible = true;
            }
            else if (string.IsNullOrWhiteSpace(REmailEntry.Text))
            {
                REmail2.IsVisible = true;
            }


            else
            {
                if (Regex.IsMatch(email, emailPattern))
                {
                    if (Regex.IsMatch(passwor, passwordRegex))
                    {
                        if (RpasswordEntry.Text != RcpasswordEntry.Text)
                        {
                            RCpassword.IsVisible = true;
                            RcpasswordEntry.Text = "";
                        }
                        else
                        {
                            users.UserName = Username.Text;
                            users.Password = RpasswordEntry.Text;
                            users.ConfirmPassword = RcpasswordEntry.Text;
                            users.Email = REmailEntry.Text;



                            db1.AddUsers(users);

                            await Navigation.PushAsync(new MainPage());
                        }
                    }
                    else
                    {
                        Rpassword.IsVisible = true;
                    }
                }

                else
                {
                    REmail.IsVisible = true;
                }
            }
        }
        else
        {
            Rusername.IsVisible = true;
        }
    }
    else
    {
        REmail3.IsVisible = true;
    }
}