newbie - sessions

[monki]

I am trying to build a simple shopping cart

I am trying to store the contents of the cart in the session.

I have 2 questions

1) I am trying to see if the product is exists in the session, if it is
then rather than add the product again I want to add to the quantity of the
existing product

The code I am using is
_________________________________
strProd=request.form("ProdId")
strQty=request.form("Qty")

If Session(strProd)="" Then
Session(strProd) = strQty
Else
strOldQty=Session(strProd)
strNewQty=(strQty+strOldQty)

Session(strProd) = strNewQty
End if
_________________________________

Rather than adding the quantities the code puts the second qty after the
first I.e. 11 rather than 2

How do I get the addition to work. I have tried several different methods
but always get the same results?

2) Is this the best way of building a simple cart. I have thought about
just adding the cart into a database however I cant work out how to delete
the records if the session times out or is abandoned. I have looked at
Session_OnEnd but can not find any code examples of how this is used

Thanks in advance

J

 

[Evertjan.]

monki wrote on 29 mei 2004 in microsoft.public.inetserver.asp.general:

Rather than adding the quantities the code puts the second qty after
the first I.e. 11 rather than 2

How do I get the addition to work. I have tried several different
methods but always get the same results?

We are talking vbscript:

session("...") always returns a string

string + string concatenates the strings just like string & string

response.write "3" + "4" ' shows 34

change the strigns to numberic and they are added

response.write 1*"3" + 1*"4" ' shows 7

2) Is this the best way of building a simple cart. I have thought
about just adding the cart into a database however I cant work out how
to delete the records if the session times out or is abandoned. I have
looked at Session_OnEnd but can not find any code examples of how this
is used

do not use Session_OnEnd, it is unreliable, it will not fire if the
server crashes. Do not add a final record till the final acknowledgement.

I think you still have much to learn about ASP and vbscript, if you do
not know when a number is realy a string and a reliable cart is probably
still out of your reach.