MVC3 DropDownListFor not populating selectedValue - asp.net-mvc-3

Question

I feel like I'm taking crazy pills. I have a dropdownlist for a view that reads from our database all of the wine producers we have. I want to set the selectedValue to a particular ID driven by the referring page. I can see it picks up the selectedValue in debug, I see the selected value populated (906 for this example), but it doesn't set the dropdownlist to the correct value when the page is rendered, it always defaults to 1 for the default value. I've tried creating the selectList in razor as opposed to my controller, but nothing works. Any help on this would be appreciated, I'm guessing it is something small.
Controller:
if (User.IsInRole("admin"))
{
if (ID != 0)
{
ViewBag.ProducerSelect = new SelectList(db.Producers.OrderBy(p => p.Name), "ProducerID", "Name", ID);
}
else
{
ViewBag.ProducerSelect = new SelectList(db.Producers.OrderBy(p => p.Name), "ProducerID", "Name");
}
}
View:
if (User.IsInRole("producereditor"))
{
<h3>#ViewBag.ProducerName</h3>
}
else
{
<div class="editor-label">
#Html.LabelFor(m => m.Wine.ProducerID, "Producer")
</div>
<div class="editor-field">
#Html.DropDownListFor(m => m.Wine.ProducerID, ViewBag.ProducerSelect as SelectList)
</div>
}
Tried the below but no success:
ViewBag.ProducerSelect = new SelectList(from p in db.Producers
orderby p.Name
select new { p.ProducerID, p.Name }
, "ProducerID", "Name", ID);

Answer 1

If you want to preselect an item, You set that value to your ProducerId property.
var yourViewModelObj=new YourViewModel;
yourViewModelObj.Wine.ProducerId=906; //or whatever value you want
return View(yourViewModelObj);
Suggestion : For better code readablity/Maintenance, Try to avoid ViewBag / ViewData and use a ViewModel to pass the data.
I would add a Property to my ViewModel to hold the Collection of Producers
public class WineViewModel
{
//Other Existing properties also
public IEnumerable<SelectListItem> Producers{ get; set; }
public string SelectedProducer { get; set; }
}
Then in yout GetAction method, you can set the value like this, If you want to set one select option as the default selected one.
public ActionResult CreateWine()
{
var vm=new WineViewModel();
//The below code is hardcoded for demo. you mat replace with DB data.
vm.Producers= new[]
{
new SelectListItem { Value = "1", Text = "Prodcer A" },
new SelectListItem { Value = "2", Text = "Prodcer B" },
new SelectListItem { Value = "3", Text = "Prodcer C" }
};
//Now let's set the default one's value
vm.SelectedProducer = "2";
return View(vm);
}
And in your Strongly typed View,
#Html.DropDownListFor(x => x.SelectedProducer,
new SelectList(Model.Producers, "Value", "Text"), "Select Producer")
The HTML Markup generated by above code will have the HTML select with the option with value 2 as selected one.

Answer 2

I figured this out. I had ViewModel.wine.ProducerID elsewhere on the page in a hidden field, and that defaults to 1, so I just assigned that to passed in value, and it worked great. I knew it was something like that. Thanks!

Answer 3

User a ViewModel ex WineViewModel
public class WineViewModel
{
public Wine Wine { get; set; }
public SelectList PProducerList { get; set; }
public WineViewModel() { }
public WineViewModel(Wine wine)
{
this.Wine = wine;
}
}
Try the following in your controller
var model = new WineViewModel( selectwine);
model.ProjectTypeList = new SelectList( from p in db.Producers
orderby p.Name
select new { p.ID, p.Name }, "ID", "Name")
notice how I am exclusively declaring which is the ID and which is the Value in my SelectList
Then in your view do
#Html.DropDownListFor(model => model.Wine.ProducerID, Model.ProjectTypeList)