addPersonButtonClick.cs

private void _btnAddPerson_Click(object sender, EventArgs e)
{
    var name = _inputName.Text;
    var lastName = _inputLastName.Text;

    var id = PeopleRepository.SavePerson(new Person
    {
        Name = name,
        LastName = lastName
    });

    var person = PeopleRepository.GetPerson(id);

    if (person == null)
        Toast.MakeText(this, $"Person: Name={name}, LastName={lastName} wasn't properly saved!", ToastLength.Long).Show();
    else
        Toast.MakeText(this, $"Person saved, details: {person}", ToastLength.Long).Show();

}