Event.Value population delay

Question

I have some forms that require barcodes for scanning purposes.  In order to generate these barcodes, I create a text field using a 3of9 font, set it as read only, and script the value as:
     event.value="*"+this.getField("FIELDNAME").value+"*";
This normally goes off without a hitch, but i'm having an issue with passing that value from FIELDNAME when FIELDNAME is a scripted value.  For example, in one situation, FIELDNAME is a locked text field with a scripted value of:
     var A = this.getField("PART1").value;
     var B = this.getField("PART2").value;
     var C = this.getField("PART3").value;
     var strPart1 = String(A);
     var strPart2 = String(B);
     var strPart3 = A<2?"0"+String(C):String(C);
     var fullname =  (strPart1 + strPart2 + strPart3);
     event.value = fullname;
This is being done because "PART1" is a data-mapped field of 7 digits, "PART2" is a data-mapped field of 2 digits, and "PART3" is a data-mapped field of 2 digits that often starts with a leading 0.  They have to be concatenated for the barcode to be proper, but there is no data map for a fully concatenated value.  The FIELDNAME field populates fine, but the barcode only outputs "**".  As soon as any other field in the form is manually filled, the barcode changes to the appropriate "*FIELDNAME*".
I have no validation triggers set anywhere in the form, but this seems to be an event validation gone awry.
Any ideas?
Thanks in advance,
A.

Answer 1

I tried to use the appropriate valueAsString property, but was having problems getting it to work properly.  However, setting that calculation order got it all worked out.  A thousand thanks, sahib.  May your camels always have healthy calves.
-A.
--Edit, found the problem with the valueAsString property I was having (leftover junk from declaring a var as an int).  You're correct, that's a much more efficient way to handle the same issue.  For any interested parties, here's how it turned out:
     var A = this.getField("FIELD1").valueAsString
     var B = this.getField("FIELD2").valueAsString;
     var C = this.getField("FIELD3").valueAsString;
     var fieldname =  (A+B+C);
     event.value = fieldname;