I want to prevent duplicate code assignments within the same workbook but across several worksheets. The entries will be manually assigned and entered, and ideally I’d like to have, e.g., data validation come up with an error message and stop on entry attempt. I’m looking for a solution that does not involve VB or .xlsm.
I’ve referenced several online sources — as well as this SU post — but everything I’ve found seems to be intended for use within the confines of a single worksheet reference.
I’ve tried experimenting on my own, but wasn’t able to get validation to work when attempting to reference multiple ranges located on multiple sheets. I then thought to use a Data sheet that aggregates all the entries across the worksheet input ranges into one table, and applied Data Validation on that range instead. Unfortunately, it seems that Data Validation will not trip on initial input; only if you refresh the cell — e.g., F2,Enter — does the error message come up.
Any suggestions on how to accomplish this would be greatly appreciated, thank you!
