protected void BtnAddList_Click(object sender, EventArgs e)
{
if (Page.IsValid)
{
//get cart from session and selected item from cart
CustomerList cus = CustomerList.GetList();
Customer cartItem = cus[selectedCustomer.CustomerID];
//if item isn’t in cart, add it; otherwise, increase its quantity
if (cartItem == null)
{
cus.AddList(selectedCustomer);
}
Response.Redirect("ContactList.aspx", false);
}
}