Hi I have developed a Point of sale Invoice Form from the WorkOrder/Invoice forms found in the WorkOrder seminar. I use a barcode scanner to populate a product into the subform using the following vba code DoCmd.GoToControl "ProductID"
    DoCmd.GoToRecord , , acNewRec
    ProductID = ProductComboB
    Description = ProductComboB.Column(2)
    UnitPrice = ProductComboB.Column(3)
    Quantity = 1
    Notes = DLookup("Notes", "ProductT", "ProductID=" & ProductComboB)
    IsTaxable = DLookup("IsTaxable", "ProductT", "ProductID=" & ProductComboB)
    ProductComboB = ""
    DoCmd.GoToControl "ProductComboB"
    Me.Refresh

What I would like to achieve is when someone scans a product during a sale the vba code checks to see if there is an existing product with the same Product ID already entered in the subform. If the product ID is already entered in the subform then just enter a quantity of 1 to the quantity field already existing. Else enter in a new record in the subform if the product id is not there. Many thanks in advance Andrew.  The present VBA code fires in the after update event of the ProductComboB

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Reply from Richard Rost:

Well, there are a couple of ways you could do it. One would be to DLOOKUP the values in your subform and see if it's there. If so you could modify it with a recordset or some UPDATE SQL command and then refresh the subform.

Another way you could do it would be to crawl down the lines of your subform using DoCmd.GoToRecord commands and see if that ID exists. If so, just manually add the value.

Your choice. :)