private void btn_reg_Click(object sender, RoutedEventArgs e)
 {
     DbLitecontroller db = new DbLitecontroller();             
     string res=db.agregarUsuario(txt_email.Text, txt_name.Text, txt_lastName.Text, txt_Password.Password);
     if (res.Equals("ok"))
     {
         Application.Current.MainWindow.Visibility = Visibility.Visible;
         this.Close();
     }
     else
     {
         MessageBox.Show(res);
     }
 }
 public LoginWindow()
 {
     InitializeComponent();
     dbMP = new DbLitecontroller();
 }