[RESOLVED] MVC 3 DropDownListFor problem

Hello.

I'm using VS2010, MVC 3, Razor and Entity Framework 4.

I want to have a drop down list with list of all countries from the Countries table. And in my model, I have just a single country id (Guid).

So, in my Model, I have:

Code:

---

public Guid? CountryID
{ get; set; }

---

In my Controller, I have:

Code:

---

ViewBag.Countries = from e in new MyEntities().Countries select e;

---

And in my View, I have:

Code:

---

@Html.DropDownListFor(m => m.CountryID, new SelectList(ViewBag.Countries, "CountryID", "Name"), "")

---

If I choose something or not, i get the "Value cannot be null", on the View line of the code (@Html.DropDown...). What am I doing wrong?

Also, cause I'm totally new to MVC and Entity Framework, is there a better way to achieve this? I'm Googling this for few hours now with no results...

EDIT: I have just seen I've posted in the wrong forum section, so please, redirect this. Sorry.

Quote:

---

Originally Posted by gavio

EDIT: I have just seen I've posted in the wrong forum section, so please, redirect this. Sorry.

---

No problem :)

Moved to the MVC Forums.

Gary

Ok. Got it working with a little bit of a different approach.

Model:

Code:

---

public UserRegistrationModel()
{
        this.InitializeCountries();
}

private void InitializeCountries()
{
        FarmerEntities fe = new FarmerEntities();
        var query = from c in new FarmerEntities().Countries select new { ID = c.ID_Country, Name = c.ISO_Code };
        var countries = query.ToSelectList(c => c.ID.ToString(), c => c.Name);

        this.Countries = countries;
}

public Guid? { get; set; }

public IEnumerable<SelectListItem> Countries
{ get; set; }

---

Controller:

Code:

---

UserRegistrationModel model = new UserRegistrationModel();

return View(model);

---

View:

Code:

---

@Html.DropDownListFor(m => m.Country, Model.Countries, "")

---

Also, you need to implement this extension:

Code:

---

public static class EnumerableExtensions
{
        public static IEnumerable<SelectListItem> ToSelectList<TItem, TValue>(this IEnumerable<TItem> items, Func<TItem, TValue> valueSelector, Func<TItem, string> nameSelector)
        {
                return items.ToSelectList(valueSelector, nameSelector, x => false);
        }

        public static IEnumerable<SelectListItem> ToSelectList<TItem, TValue>(this IEnumerable<TItem> items, Func<TItem, TValue> valueSelector, Func<TItem, string> nameSelector, IEnumerable<TValue> selectedItems)
        {
                return items.ToSelectList(valueSelector, nameSelector, x => selectedItems != null && selectedItems.Contains(valueSelector(x)));
        }

        public static IEnumerable<SelectListItem> ToSelectList<TItem, TValue>(this IEnumerable<TItem> items, Func<TItem, TValue> valueSelector, Func<TItem, string> nameSelector, Func<TItem, bool> selectedValueSelector)
        {
                foreach (var item in items)
                {
                        var value = valueSelector(item);

                        yield return new SelectListItem
                        {
                                Text = nameSelector(item),
                                Value = value.ToString(),
                                Selected = selectedValueSelector(item)
                        };
                }
        }
}

---