MVC3 validate only one entity in ViewModel - asp.net-mvc-3

Question

I have an mvc3 create page using a View Model with 2 entities
like
class ViewModel1{
public User user{get;set;}
public Company company{get;set;}
}
where User and Company are EF4 entities(tables). I need to use a single page to create both(related) tables. Now the Company entity is optional under some conditions and I use jQuery to hide the corresponding section in the view.
However since company has required fields , the post back create function has ModelState.Valid as false.
What I want to do is if the Company section is hidden, I would like to skip validating the Company entity in ViewModel in Server( I avoid validation of hidden elements in Client).
Maybe there is a better and more proper approach to this?

Answer 1

What you have shown is not a view model. You call it a view model but it isn't because it is referencing your EF domain entities.
A more realistic view model would look like this:
class ViewModel1
{
public UserViewModel User { get;set; }
public CompanyViewModel Company { get; set; }
}
or even flattened out and containing only the properties that your view needs:
class ViewModel1
{
public int UserId { get;set; }
[Required]
public string FullUserName { get;set; }
[Required]
public string CompanyName { get; set; }
}
Now depending on your specific requirements about view model validation your UserViewModel and CompanyViewModel classes will be specifically designed for them.

Answer 2

Instead of putting the entities directly in the view model, put the properties for the entities in the view model and map between the view model and the actual entity objects on the server. That way you can control what properties are required for your view. Create some custom validation rules to validate that the required company properties are there when some company information is required. To do this on the server, you can have your view model implement IValidatableObject and implement the logic in the Validate method. On the client you can add rules to the jQuery validate plugin for the "required if" properties.
public class UserCreationViewModel : IValidatableObject
{
[Required]
public string Username { get; set; }
[Required]
public string FirstName { get; set; }
...
public string CompanyName { get; set; }
public string CompanyEmail { get; set; }
public IEnumerable<ValidationResult> Validate( ValidationContext context )
{
if (!string.IsNullOrEmpty(CompanyName) && string.IsNullOrEmpty(CompanyEmail))
{
return yield new ValidationResult("Company Email is required if you specify a company", new [] { "CompanyEmail" });
}
}
}
I'm not sure what I would do on the client-side. You have a choice of either adding specific rules to the validate plugin directly, but it might be hard to make it look exactly the same as using the unobtrusive validation that MVC adds. Alternatively, you could look at adding/removing the unobtrusive attributes from the "required if" elements using jQuery depending on the state of the elements that trigger their requirement. I suggest trying both ways -- look at the docs for the validate plugin to see how to add custom rules and examine the code emitted by the MVC framework for the unobtrusive validate to see what you would need to add to make that work.
Another possibility would be including/removing a partial view with the company properties in the from based on whether the company information is required or not. That is, type in a company name and use AJAX to grab the inputs required for the company and add them to the form. If the company name is deleted, delete the elements. Leave the server-side validation the way it is, but in the partial view mimic the HTML that the framework would add in for unobtrusive validation. This is sort of the best of both worlds as the jQuery code is much simpler and you get consistent validation, too.

Answer 3

There are many ways you can achieve,
1) more commonly donot use [Required] attribute on Company object, but have proper validation for parameters inside Company object.
In this case if Company object is null still validation will pass, but if Company object isnot null it will validate each properties.
2) If validation involves some complex business logic, then go for Self Validating Model. (inherit from IValiddatableObject, and override Validate(...).
3) By code, in the controller.
if(model.company == null)
this.ModelState.Keys.Where(k => k.Contains("company")).ToList().ForEach(k => this.ModelState.Remove(k));
first two are best approved approaches, third is just another way to achieve your functionalities