private void Button_Click(object sender, RoutedEventArgs e)
{
Model1 db = new Model1();
int a = Convert.ToInt32(idtxt.Text);
var cls = db.Clients
.Where(c => c.id_user == a)
.FirstOrDefault();
cls.username = username.Text;
cls.password = password.Text;
cls.last_name = last.Text;
cls.first_name = first.Text;
cls.phone = phone.Text;
cls.email = email.Text;
db.SaveChanges();
MessageBox.Show("Данные о клиенте изменены!");
ClientView cv = new ClientView();
cv.Show();
Close();
}