How do you ignore/persist values in MVC when your view-model doesn't have as many fields as your domain model?

Question

I have a site where I'm using fluentNhibernate and Asp.net MVC. I have an Edit view that allows user to edit 8 of the 10 properties for that record (object). When you submit the form and the Model binds, the two un-editable fields come back in the view-model as Empty strings or as default DateTime values depending on the type of property.

Because I'm also using AutoMapper to map my view-model to my Domain Entity, I cannot just load a fresh copy of my object from the database and manually set the 2 missing properties. Whats the best way to persist those fields that I don't want edited?

One way that does work is to persist the values in hidden Input fields on my View. That works but feels gross. I appreciate any recommendations. Is there a way in my AutoMapper to configure this desired functionality?

UPDATE: Ok, So I guess I'm not trying to ignore the fields, I'm trying to make sure that I don't persist null or empty string values. Ignoring the fields in AutoMapper does just that, they get ignored and are null when I attempt to map them before Saved to my repository.

Answer 1

You can tell Automapper to ignore the 2 properties:

Mapper.CreateMap<Source, Destination>()
.ForMember(dest => dest.SomeValuefff, opt => opt.Ignore());

Possible related question.

Answer 2

The asp.net mvc DefaultModelBinder is extensible, and you can override it to create your own binding schema. But this will involve more work than two "hidden Input fields", which , in my point of view, is not that gross.