ASP.NET MVC - server-side validation for value types

Question

I have a model that contains value types (e.g. bool, DateTime, enums, etc) and I've marked the properties with the [Required] attribute.

I load the page, don't supply a value for anything, and submit the form. Client-side validation is turned off. Obviously the ModelState is invalid.

When the form is returned to the client however, these fields are populated with the type's default value (e.g. false, DateTime.MinValue, the first enum value, etc). This is not really what I want, I want the fields to stay empty.

Currently I'm getting round this by making the properties nullable (e.g. bool?). Is this the "correct" thing to do? Or should I be doing something else to ensure that MVC isn't automatically populating value-type properties with the default value?

Or maybe I'm going to be told I should be using a View Model class which only has strings...? Unfortunately it's a bit late for that, partly due to requirements and partly due to my inexperience. I'll save that til the next project! — Graham Clark
– Graham Clark, Commented Jun 28, 2011 at 9:04
I would stick with the nullable option. This is something I've wanted to do and I couldn't find an easier solution apart from perhaps not using the MVC clientside validation and creating my own. That seemed like too much work though. — dreza
– dreza, Commented Jun 28, 2011 at 11:09

BonyT · Accepted Answer · 2011-06-28 10:09:39Z

1

I'm assuming you want the fields in the form to remain empty on next visit - in which case Nullable types is one way to go yes. Strings is another.

Note: I tend not to use Enums in my ViewModel, but rather nullable ints - I find it easier.

Another trick is to leave 0 for Enums to be used in Combo boxes unmapped, and then add a "Please Select" (value=0) option. In this case you are better off without a nullable type since 0 is useful.

All of this works much better if you have a separate ViewModel from your Domain object - use Automapper of equivalent to map between them. This allows you to have one set of types in your ViewModel designed for your UI, without compromising what you have in your Domain Layer.

edited Jun 28, 2011 at 10:09

answered Jun 28, 2011 at 9:57

BonyT

11k5 gold badges34 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

ASP.NET MVC - server-side validation for value types

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related