Undoing Changes in Subform 1

[jaydy]

Hi,

I'm currently doing an invoice database. So I have one subform in my invoice form that basically lists all the orders. Each row has the fiels product, quantity and the total amount. My problem here is, I've created a code that after you update the quantity, it automatically deducts from the warehouse that product is located in. But, if the user suddenly changes her mind and decides to change the quantity like for example it was originally 5 then she changes it to 2, instead of adding 3 more to my inventory it just deducts 2 more.

How can i resolve this?

Your suggestions are most welcome.

 

[mndrlion]

You don't want to decrement the quantity from inventory you want to decrement the change in quantity.

To start, in the Current event in the subform, store the quantity in a variable - say intPrevQty. Then after the quantity gets updated, calulate the change in quantity as (current quantity - intPrevQty). Use that value to update the inventory.

Note that if you update the inventory before the subform record is saved, you could use the OldValue property of the Quantity control rather than saving the old value in a separate variable.

 

[jaydy]

Thanks, I used the old value property and now it works. Thanks a lot