private async void ConfirmPassword()
{
var pass = Contrasena.Substring(0, ConfirmarContrasena.Length);
if (pass != ConfirmarContrasena)
{
await Application.Current.MainPage.DisplayAlert(
"DomiMant Apps",
"La contraseña no coincide con la anterior",
"Ok");
ConfirmarContrasena = "";
}
}