If you want to Insert item details using barcode in axapta then this code can help you. Here TableItemTrans is item transaction table. This is not a exact code but this can help you to get hints to implement barcode in your customized module.
ItemId ItemId;
InventTable InvTable;
InventItemBarcode InventItemBarcode;
TableItemTrans _TableItemTrans;
;
ItemId = this.text();
If (ItemID != "" && !InventTable ::exist(ItemId))
{
InvTable = InventTable::find(InventItemBarcode::findBarcode(this.text(), False, False).itemId);
if (InvTable.ItemId != '')
{
info(StrFmt("Itemid using Barcode : %1.",InvTable.ItemId));
_TableItemTrans.ItemId = InvTable.ItemId;
this.text(InvTable.ItemId);
}