asp.net - MVC 5 Multiple Models in a Single View

Question

Could somebody please provide an example of how to combine two models within one view?

Currently I have a page called RecordCard which contains:

@model IEnumerable<WebApplication1.Models.Weight>

This is provided by the following code in the AccountController:

public ActionResult RecordCard()
{
    var UserId = User.Identity.GetUserId();
    var weightModel = from m in db.Weights where m.UserId == UserId select m;
    return View(weightModel);
}

The RecordCard page also contains a form which is bound to the following class:

public class AddWeightModel
{
    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "Stone")]
    public Nullable<short> Stone { get; set; }

    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "Pound")]
    public Nullable<short> Pound { get; set; }
}

However, these are two individual models with different purposes, so how do I combine to a single model that contains an IEnumerable list and set of form elements that will ultimately post to the AccountController correctly to add a record to the database using the following code:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult RecordCard(Weight Model)
{
    if (ModelState.IsValid)
    {
        using (WebApplication1Entities db = new WebApplication1Entities())
        {
            Weight weight = new Weight();
            weight.UserId = User.Identity.GetUserId();
            weight.Stone = Model.Stone;
            weight.Pound = Model.Pound;
            weight.Date = System.DateTime.Now;

            db.Weights.Add(Model);
            db.SaveChanges();
        }
    }
    return View(Model);
}

I have included the Weight class below:

public partial class Weight
{
    public int Id { get; set; }
    public string UserId { get; set; }
    public Nullable<short> Stone { get; set; }
    public Nullable<short> Pound { get; set; }
    public Nullable<System.DateTime> Date { get; set; }
}

Also here is the WebApplication1Entities class which declares the Weight table as Weights:

public partial class WebApplication1Entities : DbContext
{
    public WebApplication1Entities()
        : base("name=WebApplication1Entities")
    {
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        throw new UnintentionalCodeFirstException();
    }

    public virtual DbSet<Weight> Weights { get; set; }
}

Please explain what needs to be modified and how, no matter what I try to read, follow and implement, I seem to be missing something.

Any help would be much appreciated :-)

Answer 1

I would say this is good example of using ViewModel here. I would suggest something like -

Create ViewModel with the composition of the two classes

public class AddWeightModel
{
    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "Stone")]
    public Nullable<short> Stone { get; set; }

    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "Pound")]
    public Nullable<short> Pound { get; set; }
}
....
public partial class Weight
{
    public int Id { get; set; }
    public string UserId { get; set; }
    public Nullable<short> Stone { get; set; }
    public Nullable<short> Pound { get; set; }
    public Nullable<System.DateTime> Date { get; set; }
}
.....
public class WeightViewModel
{
    public IList<AddWeightModel> AddWeightModel { get; set; }
    public Weight Weight { get; set; }
}

Then change your view to accept the view models -

@model WeightViewModel

Finally modify your controller to cope with the change -

public ActionResult RecordCard()
    {
        var UserId = User.Identity.GetUserId();
        var weightModel = from m in db.Weights where m.UserId == UserId select m;
        var viewModel = new WeightViewModel
        {
            Weight = weightModel,
            AddWeightModel = new List<AddWeightModel>(){}
        };
        return View(viewModel);
    }

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult RecordCard(WeightViewModel viewModel)
{
    Weight Model = viewModel.Weight;
    if (ModelState.IsValid)
    {
        using (WebApplication1Entities db = new WebApplication1Entities())
        {
            Weight weight = new Weight();
            weight.UserId = User.Identity.GetUserId();
            weight.Stone = Model.Stone;
            weight.Pound = Model.Pound;
            weight.Date = System.DateTime.Now;

            db.Weights.Add(Model);
            db.SaveChanges();
        }
    }
    return RedirectToAction("RecordCard");
}