ดึงราคาจากPO ก่อน Movement/Transfer จากรายงาน inventTranlist

display real PricePerUnit()
{
  real realRet;
  PurchIdBase ret;
  InventTrans  inventTrans_PONO;

  PurchLine  purchline;
  ;

     while select inventTrans_PONO
     where inventTrans_PONO.TransType == InventTransType::Purch
     && inventTrans_PONO.ItemId    == InventTrans.ItemId
     && inventTrans_PONO.InventTransId <= InventTrans.InventTransId
     {
        ret = inventTrans_PONO.TransRefId;
     }
  if(inventTrans.TransType == InventTransType::Purch)
   {
      ret = "";
   }

 if(ret != "")
{
      select purchline
      where purchline.PurchId == ret
         && purchline.ItemId == InventTrans.ItemId;

     realRet = purchline.PurchPrice;
      }
  else
 {
    realRet = 0;
  }

  return  realRet;
}