CODEWITHSUNDEEP
asp.net-mvcentity-framework
NoPyGod
NoPyGod

Reputation: 5067

Entity Framework ASP.NET MVC private model fields

There is a field in our database which really ought to be a boolean, but for some reason the original developers made it a CHAR which will either be set to "1" or "0".

    [Column("CHARGEABLE")]
    [StringLength(1)]
    private string Chargeable { get; set; }

I want my model to represent this field as a boolean so I figured I could add a property to my model to wrap it:

    [NotMapped]
    public bool ChargeableTrue
    {
        get
        {
            return Chargeable == "1" ? true : false;
        }
        set
        {
            Chargeable = value ? "1" : "0";
        }
    }

Now on my View I just display the EditorFor ( ChargeableTrue ), but when I click save it doesn't actually update it.

I think what is happening is that when the model is being updated, it's still attempting to get the value of 'Chargeable' from the View, even though I haven't displayed it there. And since there is no input field, it just gets null and ends up saving that to the database.

        if (ModelState.IsValid)
        {
            db.Entry(call).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }

What is one expected to do in this situation?

Upvotes: 0

Views: 986

Answers (2)

kamranicus
kamranicus

Reputation: 4387

Based on KMan's answer, here's the extended version just in case you're not familiar with creating view models.

The idea is that your domain object is not really what you want to be updating exactly from your views. Instead, you create a go-between that can also include view-specific items (like a list of objects to populate a drop-down).

public class MyViewModel {
    public bool Chargeable { get; set; }
}

Now you can do this:

@* In view *@
Html.EditorFor(m => m.Chargeable)

// In controller
public ActionResult Save(MyViewModel model) {
    if (ModelState.IsValid) {
        var domainObject = new MyObject() {
            Chargeable = model.Chargeable ? "1" : "0"
        };

        // the rest of your code using domainObject
    }
}

I'd consider just creating an overload of your domain object's constructor that accepts your view model to keep the mapping in one place. I typically use a tool like AutoMapper to map objects or manual extension methods.

A view model typically contains a sub-set of your domain object's properties, but can contain all of them or more properties like lists, visbility states, etc. They come in incredibly useful and I've never done a MVC project where I haven't used them.

Upvotes: 2

Per Kastman
Per Kastman

Reputation: 4504

Use a view model and make your mapping on the controller.

Upvotes: 2

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