That isn't a field you should normally have to change as the business object should make sure it is set correctly when the right conditions are met.

If you must change it, I would suggest evaluating the result of the ValidateGroupMultipleSO() method.  If it returns 0, multiple SOs have been applied, if it returns 1, it either only has one SO applied or it doesn't have an SO applied.

I am struggling on how to evaluate the result of ValidateGroupMultipleSO().  Do you use BusObj to get the variable?

I am struggling on how to evaluate the result of ValidateGroupMultipleSO().  Do you use BusObj to get the variable?

nRetVal = 0 : nRetVal = oBusObj.ValidateGroupMultipleSO()
If nRetVal = 0 Then
    ' Multiple SOs applied.
Else 
    ' One or no SOs applied.
End If

Trying to message box where the issue is, but I get the Company code return then the script just errors out.  And it does this when right when I create a new invoice or when I pull up a previous one.

If oSession.CompanyCode = "ROI" then
retval = oSession.AsObject(oSession.UI).Messagebox( ".company", oSession.CompanyCode)

retVal = 0
multiSO = ""
multiSO = oBusObj.ValidateGroupMultipleSO()
retval = oSession.AsObject(oSession.UI).Messagebox( "multi", multiSO)

	If multiSO = 0 then

	retVal = 0
	nSOno = ""

	retVal = oBusObj.GetValue("SalesOrderNo$", nSOno)

		if Left(nSOno, 2) = "81" then

		retVal = oBusObj.SetValueNoValidate("MultipleSalesOrdersApplied$", "Y")

		Else

		retVal = oBusObj.GetValue("SalesOrderNo$", nSOno)

		retVal = oBusObj.SetValueNoValidate("MultipleSalesOrdersApplied$", "N")

		end if
	end if	
end if

Couple issues.

ValidateGroupMultipleSO() returns a numeric value so your multiSO variable should be initialized to 0 not an empty string.

The MessageBox method only accepts string values passed to it.  You also don't have a valid value in the first argument, use a blank string instead ("").  For the second argument, use CStr() on your multiSO variable or join it to an empty string using the & operator, like "" & multiSO.

This shows my lack of knowledge, completely lost on your last explanation, but did get it to work.  It only works when I close the Invoice data entry screen and reopen the batch.  If you don't mind could you point out the exact corrections you were referring to above.  This is the version I got to work on a table post-read.

'change read only field back to default value for multiple SO invoice

If oSession.CompanyCode = "ROI" then

retVal = 0
retVal = oBusObj.ValidateGroupMultipleSO()

	If retVal = 0 then

	retVal = 0
	nSOno = ""

	retVal = oBusObj.GetValue("SalesOrderNo$", nSOno)

		if Left(nSOno, 2) = "81" then

		retVal = oBusObj.SetValueNoValidate("MultipleSalesOrdersApplied$", "Y")

		Else

		retVal = oBusObj.GetValue("SalesOrderNo$", nSOno)

		retVal = oBusObj.SetValueNoValidate("MultipleSalesOrdersApplied$", "N")

		end if
	end if	
end if