cookies for eshop basket

[ktsirig]

Hello!
I want to create an eshop basket page for my website.
In the page of each product there is a button which when I press sets a cookie with the value of the respective product_id, using the following code:
<asp:Button ID="btbasket" runat="server" Text="Buy this product" />

In the code behind file, I have the following:


Protected Sub insert_cookie(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles btbasket.Click
Dim MyCookie As New HttpCookie("eshopCookie")
MyCookie.Value = MyCookie.Value & product_code
Response.Cookies.Add(MyCookie)
MyCookie.Expires = DateTime.Now.AddHours(12)
End Sub
Then, when the user wants to see all the things he/she has ordered, they visit the Basket.aspx page,
which has this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim colCookies As New ArrayList()
For i As Integer = 0 To Request.Cookies.Count - 1
colCookies.Add(Request.Cookies(i))
Next

grdCookies.DataSource = colCookies
grdCookies.DataBind()
End Sub

and, in the .aspx file,
<asp:GridView
id="grdCookies"
Runat="server"/>



But my problem is that the gridview only shows 1 product_id, and, in particular, tha last product the user has selected a he browses the list of the available products...
Is there something else I must do to store all selected product_ids in the cookie and then retrieve them in Basket.aspx page? Must I use different cookie each time?
Thank you for your time...