Point of Sales

Question

Hi. I'm currently developing a POS system in C# with SQL Server as the database. In my database, I have a product table that contains the following fields: barcode(primary key) , productID,productName ,productQty ,productSize, and productUnitPrice.

In my GUI, I have a TEXTBOX for the barcode, another TEXTBOX for the quantity,and a LISTVIEW for the cart. My problem is, How 

can I add the product inside the LISTVIEW based on the barcode that was entered on the barcode TEXTBOX? 

Any suggestions or ideas? Thank you.