An application on which I am working begins with a SharePoint custom list, into which a user enters various data. Then the list entry triggers a work flow which sends mail, etc.
One of the fields is a text string. An edit that's been requested is to raise an error if the value of the entered column is found in a column of a SharePoint list.
Does anyone have any pointers on how to specify a validation of the type "data is found in sharepoint list"?
Thank you!