Question

I’m trying to get my head around related data for use with a master detail scenario using EF in MVC. Searching StackOverflow got me on the road for a good part, but I’m running into problems while saving my data. As more examples on StackOverflow i use a person/address set up, and for the person as well as the address (which is one-to-many) i only use part of the entities properties on my views. With the default scaffold this results in an error, but for the person entity i managed to solve that using the the code below. But for the Address entity I now get the same error and i don’t know how to solve this. Here’s what i’ve got so far:

The ContactController:

public ActionResult Edit(int id)
{
    Contact contact = db.Contacts
        .Include(c => c.Address)
        .Include(c => c.Relation)
        .Where(c => c.ContactId == id)
        .Single();
    return View(contact);
}


[HttpPost]
public ActionResult Edit(int id, FormCollection formCollection)
{
    var contactToUpdate = db.Contacts
        .Include(c => c.Address)
        .Include(c => c.Relation)
        .Where(c => c.ContactId == id)
        .Single();

    if (TryUpdateModel(contactToUpdate, "", null, new string[] { "Relation" }))
    {
        try
        {
            db.Entry(contactToUpdate).State = EntityState.Modified;
            db.SaveChanges();

            return RedirectToAction("Index");

        }
        catch (DataException ex)
        {
            ModelState.AddModelError("", "Error while saving.");
            return View();
        }
    }
    return View(contactToUpdate); 
}

The classes for my models:

namespace MyApp.Models
{
    public class Contact
    {
        public int ContactId { get; set; }
        public string Weergavenaam { get; set; }

        public virtual ICollection<Address> Address{ get; set; }
        public virtual ICollection<Relation> Relation { get; set; }
    }

    public class Address
    {
        public int AddressId { get; set; }
        public string Street{ get; set; }
        public string Postal{ get; set; }
        public string Place{ get; set; }
        public string State{ get; set; }

        public DateTime Created { get; set; }
        public DateTime Modified { get; set; }

        public virtual Contact Contact { get; set; }
    }

    public class Relation
    {
        ...
    }
}

The view for the ContactController’s Edit action:

@using (Html.BeginForm()) {
@Html.ValidationSummary(true)
<fieldset>
    <legend>Contact</legend>

    @Html.HiddenFor(model => model.ContactId)

    <div class="editor-label">
        @Html.LabelFor(model => model.Name)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Name)
        @Html.ValidationMessageFor(model => model.Name)
    </div>

    @Html.EditorFor(model => model.Address) 


    <div class="display-field">
        Created: @Html.DisplayFor(model => model.Created)
    </div>
    <div class="display-field">
        Modified: @Html.DisplayFor(model => model.Modiied)
    </div>

    <p><input type="submit" value="Save" /></p>
</fieldset>
}

The EditorTemplate for the Address model

@model MyApp.Models.Address
<fieldset>
    <legend>Address</legend>

    @Html.HiddenFor(model => model.AddressId)

    <div class="editor-label">
        @Html.LabelFor(model => model.Street)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Street)
        @Html.ValidationMessageFor(model => model.Street)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Postal)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Postal)
        @Html.ValidationMessageFor(model => model.Postal)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Place)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Place)
        @Html.ValidationMessageFor(model => model.Place)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.State)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.State)
        @Html.ValidationMessageFor(model => model.State)
    </div>
</fieldset>

Answer 1

After struggling a bit with the code I figured that for now the only way to solve the problem was to add the missing properties to the editor template using @Html.HiddenFor.
Of course I’m sure there should be a more ellegant way to get my situation working, but for now it solves my problem.

Any better solution to the issue is welcome!