CODEWITHSUNDEEP
asp.netasp.net-mvcasp.net-mvc-4
Mark Kadlec
Mark Kadlec

Reputation: 8460

ViewModel type architecture from Controller to View

I have a fairly complex class of Policies, of which I display a checkbox list of them, the user checks which one they want, and returns back to the server via ajax. The class is fairly complex:

public class Policy {
  public int PolicyId { get; set; }
  public string PolicyName { get; set; }

  ... another 15 properties ...
}

To display the list of checkboxes I really only need the Id and Name, so I've created a lightweight class PolicyViewModel that is simply:

public class PolicyViewModel {
  public int PolicyId { get; set; }
  public string PolicyName { get; set; }
}

So I then pass a List to the View and get a List back containing the selected Policies.

Another developer on my team said that he doesn't necessarily want to translate from the ViewModel to the Policy class on the Ajax call to save the selected policies, but I'm resistant to send a List of policies due to how heavy they are to send to the view, retrieving all the properties, etc.

EDIT: For clarification, on the Ajax save method, to persist to the DB, the call needs a list of the full Policy class.

What is the best way to display this list and get back the values? Is there a better way than I am proposing?

Upvotes: 2

Views: 60

Answers (2)

user1228
user1228

Reputation:

Usually, you wouldn't need a separate model when serializing to json. Simply pluck out what you need from the domain object into an anonymous object.

return policies.Select(x => new { PolicyId = x.PolicyId, Name = x.PolicyName});

on the return trip, you shouldn't have to send anything more than the Ids of the policies that the user selected. Those can be easily mapped back to your policy objects.

public Whatever PostPolicyChoices(IEnumerable<int> ids)
{
    var checked = _context.Policies.Where(x => returnIds.Contains(x.PolicyId)); 
    // snip

boom. done.

Upvotes: 2

Nic
Nic

Reputation: 1089

I will recommend you not to work with Domain objects in your mvc application . You must work just with ViewModels, I think this is best practice for mvc projects. Take a look at Automapper and use it in your project, this will simplify your work, so this should look something like this :

in your [HttpGet] method you will have :

var model =Mapper.Map<IList<Policy>,IList<VmSysPolicy>>(yourlist)

And in your [HttpPost] method you will have :

var domainList=Mapper.Map<IList<VmSysPolicy>,IList<Policy>>(modelList);

And in your mapping configuration you will do :

Mapper.CreateMap<Policy,PolicyVmSysPolicy,>()
.ForMemeber()//Your mapping here

and 

Mapper.CreateMap<VmSysPolicy,Policy>()
.ForMemeber//mapping here

Upvotes: 2

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