I am trying to code simple membership class. First class name is Customer and it has others classes like Silver_Customer, Gold_Customer which are inherited from Customer class.
I use these classes in my simple windows application:
public Customer customer;
public Form_MURAT_TURAN()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
Product p1 = new Product("Blouse", 152.80);
Product p2 = new Product("T-Shirt", 50.25);
.....
lbProducts.Items.Add(p1);
lbProducts.Items.Add(p2);
.....
}
private void btnCustomer_Click(object sender, EventArgs e)
{
Customer customer = new Standard_Customer(txtName.Text, txtSurname.Text, 0);
customer.Name = "Mark 1";
customer.TotalAmount = 5;
gbCustomer.Enabled = false;
gbProduct.Enabled = true;
set_info(customer.customerType(), customer.Name + " " + customer.Surname, customer.TotalAmount);
}
private void btnAddToBasket_Click(object sender, EventArgs e)
{
customer.Name = "Mark 2";
}
Everything works fine except btnAddToBasket_Click method. customer.Name = "Mark 2"; line give me NullReferenceException
error but customer.Name = "Mark 1" line works.