Error messages LnF
Error messages LnF
- Error messages should always explain exactly what the user did wrong. If user cannot immediately understand what the message means; it is a bug!
- If the same error message is used for two different bugs - it is a bug!
- Errors should appear in the top of dialogues / windows in red color in bullet format. All the errors that are registered should be listed.
- The GUI should not refresh before showing the errors (if possible)
- A general guideline for whether a validation of a field should happens client side or server side is as follows: If the object/s to save can be or is expected to be inserted many places and the logic of how the object should look is the same from all these interfaces, then the check of the correctness of the values of the object/s should happen server side. Generally it is not an idea to validate data client side, since business logic should not be put in GUI!
- A general guideline for whether a validation happens on leave a field or on save screen/dialogue is as follows: If the value can be tested immediately on client side and it is fast, e.g. check whether illegal character is used, it should happen immediately. Exceptions to the rule are when fields depend on other fields, then it is better to just make sure that user is notified when he has finished all fields and is saving.
