In edit or new form have 2 fields StartDate & EndDate. How to check StartDate must be less than EndDate? (Only config on AdminCP or change source code by using a CompareValidator?) Help me solve this problem... Thank.
This issue is best solved using the new Business Rules Engine that we added to 5.0. You can create a validation rule that will check the date values and generate an error appropriately. Please use our training videos to learn how to create a business rule.