private void BtnAddCustomer_Click(object sender, RoutedEventArgs e)
{
if (!Validation())
{
return;
}
Customer customer = new Customer
{
FullName = tbCustomerFullName.Text,
CreateDate = DateTime.Today,
PhoneNumber = tbPhoneNumber.Text,
Address = tbAddress.Text
};
dr.AddCustomer(customer);
FillDG();
ResetTextBox();
}