Html.DisplayFor DropDownList problem

Question

Im using asp.net mvc 2. I have a model Supermodel that consists of 2 models TestModel1 and TestModel2. In SuperModelView Im doing the following thing:

 <%: Html.DisplayFor(x=> x.TestModel1, "TestModel1Template") %>

Its working just fine, except for the fact, that dropdownlist is populated but selected value is not set. Im using the following code for a dropdownlist in my template:

<%: Html.DropDownListFor(x=> x.Property1, (IEnumerable<SelectListItem>)ViewData["MyDDLList"], Model.Property1) %>

and its not setting the selected property. I put the code below to SuperModelView, that calls <%: Html.DisplayFor To populate the template and it works just fine. So I`m kinda puzzled, what is the difference?

<%: Html.DropDownListFor(x=> x.TestModel1.Property1, (IEnumerable<SelectListItem>)ViewData["MyDDLList"], Model.TestModel1.Property1) %>

UPDATE: I`ve tried to investigate the issue, but something is totally wrong. I can share the whole code, not sure where to put it, here or attach with separate files.

@Darin, what other parts should I share, or just share the whole model view and controller files?

Answer 1

Firstly display templates are just for displaying. If you need to edit with drop down use editor template:

<%: Html.EditorFor(x => x.TestModel1, "TestModel1Template") %>

and in your editor template:

<%: Html.DropDownListFor(x => x.Property1, Model.MyDDLList) %>

where MyDDLList is defined like:

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

and in your controller action you fill the values:

public ActionResult Foo() 
{
    var model = new SuperViewModel 
    {
        TestModel1 = new TestModel1
        {
            // Set some selected value
            Property1 = "1",

            // Fill the drop down values
            // TODO: use a repository
            MyDDLList = new SelectList(new[]
            {
                new SelectListItem { Value = "1", Text = "text 1" },
                new SelectListItem { Value = "2", Text = "text 2" },
                new SelectListItem { Value = "3", Text = "text 3" },
            }, "Value", "Text")
        }
    }
    return View(model);
}

---

UPDATE:

Here's a complete working example:

Model:

public class MyViewModel
{
    public string SelectedItemId { get; set; }
    public IEnumerable<SelectListItem> Items { get; set; }
}

Controller:

[HandleError]
public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new MyViewModel
        {
            // Preselect the second item
            SelectedItemId = "2",
            Items = new SelectList(new[]
            {
                new SelectListItem { Value = "1", Text = "item 1" },
                new SelectListItem { Value = "2", Text = "item 2" },
                new SelectListItem { Value = "3", Text = "item 3" },
            }, "Value", "Text")
        };
        return View(model);
    }
}

View (~/Views/Index.aspx):

<%: Html.DisplayForModel() %>

DisplayTemplate (~/Views/DisplayTemplates/MyViewModel):

<%: Html.DropDownListFor(x => x.SelectedItemId, Model.Items) %>