ok, so here's my situation. i've got a field that holds multiple id numbers separated by a comma. example:

(yes, the commas have to be where they are)

but the problem is that i need to make sure that someone doesn't repeat a number that is already there...like this:

how could i stop that from happening?

I'd convert the string to paragraph delimited, then use the UniqueValues() custom function to see how many unique value there are, and compare it to the number of entered values.

but is there a way to prevent it from happening other than just seeing that it does happen?

Use this calculation in the field validation.

Hi MParker,

Questions;

Is this field the one where the data is being entered?

Or, is it being used to show the result from other fields, such as from a checkbox. i.e. Concatenated in this one?

Lee