asp.net c# reduce quantity of a product

Question

1.00/5 (1 vote)

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Hi,

I'm implementing an asp.net c# web site and i'm using this code in order to reduce the
correct quantity of a product when the user press the button finish (or checkout)
"----------------------------------"

C#

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
       string aSQL = "UPDATE products set quantity=quantity-" + Request.QueryString["quant"] + "Where Id=" + Request.QueryString["Id"];
       try
       {
           con.Open();
           SqlCommand cmd = new SqlCommand(aSQL, con);
           SqlDataReader reader = cmd.ExecuteReader();
           reader.Read();
           DataTable dataTable = new DataTable();
           dataTable.Load(reader);
       }
       finally
       {
           con.Close();
       }

"-----------------------------------"
my issue that it reduces the quantity from the correct product but always (x2)
i can't understand why ? this is a very strange problem,
any help to fix this issue i will be grateful or any other relative solution to use?

thnx in advance!
Jason

Posted 25-Sep-13 5:02am

JasonTsoum77

Updated 25-Sep-13 6:27am

ridoy

v3

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Comments

Sergey Alexandrovich Kryukov 25-Sep-13 12:12pm

Not clear what you are talking about. What quantity? Why reducing correct quantity? What's the problem?
—SA

JasonTsoum77 25-Sep-13 12:22pm

well here is the whole project i have a shopping cart (cart.aspx) where i collect the products for selling when the customer push the button finish i redirect to another form (finish.aspx) where the customer choose the pay method and the (product quantity must be reduced).
My problem is I import the code that i post in finish.aspx and for some reason the product quantity reduces two times , for example if the customer select quantity 2 in my database it reduces quantity 4.
It is very strange problem and i haven't see anything else like this...thnx for your resoinse

mgoad99 25-Sep-13 14:02pm

At first glace, it sounds like the code you have to reduce the quantitiy runs twice. Have you tried setting a break point or some other debugging technique?

JasonTsoum77 26-Sep-13 8:10am

yes i have tried because i suspend something like that but all the variables had the correct values.
I tried the following solution from Karn Singh and that solved the problem.
It was very strange problem because when i tried it seperetally my code worked properly.

Thnx for your response

2 solutions

Solution 3

Jason. R you using any textbox?

Posted 14-Jul-14 14:03pm

Salman Ali Shah

Comments

[no name] 14-Jul-14 20:08pm

What possible difference could it make? Do you think that in the past year, the OP has managed to finish his homework assignment? And how would this be a solution anyway?

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Karn Singh · Accepted Answer · 2013-09-25T10:32:00

try this

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
       string aSQL = "UPDATE products set quantity=quantity-1" + Request.QueryString["quant"] + "Where Id=" + Request.QueryString["Id"];

or

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
       string aSQL = "UPDATE products set quantity=--quantity" + Request.QueryString["quant"] + "Where Id=" + Request.QueryString["Id"];

the first one is working i have same project library management where after issuing a book i have to reduce quantity by bookid.try and let me know