Using data from ComboBox and DataGrid

[Germaris]

Hi there!

I have a ComboBox (CBBUY) and a DataGrid (DGBUY).
In the ComboBox, user choose Items.
In the DataGrid appear as Objects all the chosen Items on two columns:
Item number (nber_dgc) and Quantity (qty_dgc), default value = 1 (qty_dgc is editable so user can modify the quantity).


Questions:

How do I pull out the data contained in DGBUY with updated quantities?
Should I turn Objects in DGBUY to Strings?
And how I extract the quantity from each Object in DGBUY?

Thank you very much in advance for your answers!

Best regards,
Gerry