Detecting when an Invoice exceeds the PO amount - acumatica

Question

I have created a new APTran field called UsrPOTranAmt. I would like to populate it with the PO Line amount when the user either adds a PO or a PO Line to the invoice. Later I can compare the line transaction amount to the UsrPOTranAmt and determine if the user is paying more that the PO amount.
My initial thought was to detect when the PONbr field (PO Type, PO Number, and PO Line Number fields) was updated and then set the UsrPOTranAmt field to the same value as the CuryLineAmt or Amount field that was updated by the PO or PO Line selection. I have tried to detect the field_updated event with a warning message for PONbr and POLineNbr but neither approach has worked.
public class APInvoiceEntry_Extension : PXGraphExtension<APInvoiceEntry>
{
protected void APTran_PONbr_FieldUpdated(PXCache cache, PXFieldUpdatedEventArgs e)
{
var row = (APTran)e.Row;
if (row.PONbr != null)
{
cache.RaiseExceptionHanding<APTran.PONbr>(row, row.PONbr,
new PXSetPropertyException("PO Line Number Changed", PXErrorLevel.Warning));
}
}
}
I do not receive the warning message so I don't expect that I can set the UsrPOTranAmt either with this event.

Answer 1

If you have not changed the default behavior of the Grid column of CommitChanges to True, it will not cause the postback and call the event. Give that a try.

Answer 2

The commitChanges is definitely required on a filed updated event, but here is the solution from ACM:
public class APTranExt : PXCacheExtension<PX.Objects.AP.APTran>
{
#region UsrPOTranAmt
[PXDecimal]
[PXUIField(DisplayName = "POTranAmt", Enabled = false)]
[PXDBScalar(typeof(Search<POLine.curyLineAmt,
Where<POLine.orderType, Equal<APTran.pOOrderType>,
And<POLine.orderNbr, Equal<APTran.pONbr>,
And<POLine.lineNbr, Equal<APTran.pOLineNbr>>>>>))]
public virtual Decimal? UsrPOTranAmt { get; set; }
public abstract class usrPOTranAmt : PX.Data.BQL.BqlDecimal.Field<usrPOTranAmt> { }
#endregion
}
public class APInvoiceEntry_Extension : PXGraphExtension<APInvoiceEntry>
{
#region Event Handlers
protected void APTran_RowUpdated(PXCache cache, PXRowUpdatedEventArgs e, PXRowUpdated InvokeBaseHandler)
{
if (InvokeBaseHandler != null)
InvokeBaseHandler(cache, e);
var row = (APTran)e.Row;
if(row != null && row.POOrderType != null && row.PONbr != null && row.POLineNbr != null)
{
POLine poline = PXSelect<POLine,
Where<POLine.orderType, Equal<Required<POLine.orderType>>,
And<POLine.orderNbr, Equal<Required<POLine.orderNbr>>,
And<POLine.lineNbr, Equal<Required<POLine.lineNbr>>>>>>.Select(Base, row.POOrderType, row.PONbr, row.POLineNbr);
if(poline != null)
{
cache.SetValue(row, "UsrPOTranAmt", poline.CuryLineAmt);
}
}
}
#endregion
}