How to multiply 2 values from different tables in Linq?

Question

I try to multiply 2 values from different table but it's keep error like this:

Here's my code:

    //Label12 is in datalist
    var Label12 = (Label)(((Button)sender).Parent).FindControl("Label12");  

    var item2 = from c in db.OrderTemps
                join o in db.Products
                on c.Prod_ID equals o.Prod_ID
                select new
                {
                   o.Prod_ID,
                   o.Prod_Price, //Type "Decimal"
                   c.Amount, //Type "Integer"
                   c.Total, //Type "Decimal
                   s = o.Prod_Price * c.Amount
                };

     foreach (var i in item2)
     {
        Label12.Text = Convert.ToString(i.s); //an error happen here!!
     }

Any help appreciated.

Answer 1

There is nothing wrong with you LINQ query. If no records joined, then there will be nothing to enumerate and you will skip foreach body. I think you have Label12 equal to null. Check if it really exist on senders parent.

SIDE NOTE: Why are you trying to assign text in loop? Label will keep only last value assigned.

Answer 2

Check whether your amount value in OrderTemps table is null. or Check whether you really have a controller which has the ID = Label12. Nothing wrong in your Linq query...