What is IValidatableObject for?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
It adds cross-property validation on the model class.
WHY — Validation instead of guessing?
Why interviewers care about Validation:
who only read docs from people who shipped.
and tied to .NET MVC work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1It adds cross-property validation
on the model class.
- 2Why it exists
Attributes cover single fields.
- 3I keep heavy rules
in FluentValidation when models get large.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
It adds cross-property validation on the model class. Attributes cover single fields.