Question

Got a pretty cool idea today but I’m not sure how to go about it.

I’m building a page by page form in asp.net MVC3 C#, that saves to a temporary area at the end of each page.

Now this data goes into a class with a few enumerable classes in it, so its relatively complicated.

Now, I want the user to be able to put in whatever the hell they want without validation (except security obviously), so that they can throw in whatever they want, however i want this to be soft validated.

I would like to use metadata for validation, however since this provides hard validation I can’t put this on the class that the form uses as a model (strongly typed). So, what i think is the best way to do it is to derive a class from the class on the form, and throw data annotations all over that (I’m hopeful that its possible to somehow apply an interface, but I’m assuming it isn’t)

THEN when the user wants to submit the form to our database, i want the form to go through and validate. I figure ill do this by converting the class without the data annotations that holds the data into the empty one with the dataAnnotations, and any errors that occur(essentially when the data isn’t valid) ill be able to list on the screen and tell them to fix it.

Now, another thing that i want to be able to do would be that i could somehow use the annotated class to soft validate the form when the user is on it. So i can say “we recommend you put this field in”. Rather than, “this field can’t be empty”.

So, in conclusion:

1. Is it possible to turn interfaces on and off, if so, how?
2. How would i convert classA into classB where classB is derived from classA and uses dataAnnotations
3. (Continuation of 2) during the conversion, how would i catch any data errors and list them
4. How could i soft validate off of classB on a form where the model is classA

I hope this is all possible. It seems like the cleanest way to do it. If anybody can think of a better way to do this, i am all ears… or eyes.

---

Update 1
Im under the impression that dataAnnotations would prevent me from putting any incorrect data in. However I’m doing some testing at the moment, and it seems I am able to apply incorrect data programatically. Ie null in a required field. So do data annotations only apply to validation on the page? If so, disregard my entire question.

---

Update 2
Im still looking for an answer if anybody can contribute

Answer 1

I don’t think you can do this with the validation framework in MVC. Validation is a binary operation; input is either valid or it isn’t. The ValidationResult class used to indicate success or failure during the validation process doesn’t have a ‘Maybe’ member (to use a term), it’s either yes or not.

That said, since you have control over the entire validation process, you can always define your own set of data annotation attributes and in your controller(s) test for what I assume would be ‘warnings’, and react accordingly, maybe by using a notification area that displays strings like ‘we recommend you enter data in this field” or something like that.

This is assuming that you’re not using unobtrusive client-side validation, which I wouldn’t be sure how to circumvent. I’m talking about using the ModelState variable in your controllers in a way that you can go beyond the IsValid test.