Update Multiple Models

You can create a view model that combines all the fields you need from the other models, and strongly type your view to that. Once the user submits the info back to the controller, you'll process each property appropriately.

public class RegisterViewModel()

{

//Userinfo

public string UserName {get; set;}

...

//Extended user info

public string FirstName {get; set;}

public string LastName{get; set;}

...

//Benefits

public string BenefitName {get; set;}

...

}

and then

[HttpPost]

public ActionResult Register (RegisterViewModel viewModel)

{

//grab the user info from the view model and process it

viewModel.UserName...

//grab the extended info and process it

viewModel.FirstName...

//grab the benefit info and process it

viewModel.BenefitName...

}