private void Button_Click_3(object sender, RoutedEventArgs e)
        {
            reception a = l_dg.SelectedItem as reception;

            try
            {
                a.r_date = Convert.ToDateTime(d_p_tb.Text);
            }
            catch (System.FormatException)
            {
            }

            try
            {
                a.l_date = Convert.ToDateTime(d_v_tb.Text);
            }
            catch (System.FormatException)
            {
            }
            try
            {
                a.room_num = Int32.Parse(r_num_tb.Text);
            }
            catch (System.FormatException)
            {
            }
            admin.SaveChanges();
            list_dg(l_dg);
        }
        private void Button_Click_4(object sender, RoutedEventArgs e)
        {
            reception ts = l_dg.SelectedItem as reception;

            if (ts == null)
            {
                return;
            }
            admin.reception.Remove(ts);
            admin.SaveChanges();
            list_dg(l_dg);
        }
        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            person ts = reg_dg.SelectedItem as person;

            person_id = ts.id_person;

            reception a = new reception
            {
                id_person = person_id,
            };

            admin.reception.Add(a);
            admin.SaveChanges();
            list_dg(l_dg);
        }