DropDownListFor ASP MVC4

Question

I am getting this error "CS1928:

'System.Web.Mvc.HtmlHelper' does not contain a definition for 'DropDownListFor' and the best extension method overload 'System.Web.Mvc.Html.SelectExtensions.DropDownListFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>, System.Collections.Generic.IEnumerable)' has some invalid arguments"

My controller looks like this

    public class IndexController : Controller
{
       public ActionResult Index()
       {
               EpfeSelectScreen model = new EpfeSelectScreen();

               var b = (from a in dbEntitiesErste.CONFIG_APPLICATIONS
                               orderby a.APPLICATION_ID
                               select new EPFE.CustomDataObjects.CustomObjects
                               {
                                   Text = a.APPLICATION_NAME,
                                   Value = a.APPLICATION_ID
                               });

               model.Application = b.OrderBy(x => x.Text).ToList();

               return View(model); 




       }
}

My model is this

    public class EpfeSelectScreen
{ 
    public string Search { get; set; }
    public string selectedApplication { get; set; }
    public List<SelectListItem> Country { get; set; }
    public List<CustomObjects> Application { get; set; }
    public List<SelectListItem> MetaData { get; set; }
    public List<SelectListItem> References { get; set; }
    public List<SelectListItem> ReferencedBy { get; set; }
    public List<SelectListItem> TreeView { get; set; }       

    public EpfeSelectScreen()
    {
        Country = new List<SelectListItem>();
        Application = new List<CustomObjects>();           
        References = new List<SelectListItem>();
        ReferencedBy = new List<SelectListItem>();
        TreeView = new List<SelectListItem>();        
    }
}

My CustomObjects is this

    public class CustomObjects
{
    public string Text { get; set; }
    public short Value { get; set; }
}

I have one record in my model.Application, but when that data is passed to my View i get that error.

And my View looks like this

@model EPFE.Controllers.EpfeSelectScreen
@Html.DropDownListFor(m => m.selectedApplication, Model.Application) 

How to solve this problem? What am i doing wrong? I get the same error when i try to use ListBoxFor.

Answer 1

For Adding items to drop down you can use ViewData for passing values to the dropdown.

in the controller: you can have scenario like

       IList<SelectListItem> SelectedOptions = new List<SelectListItem>();
        IList<Options> DropDownOptions = new List<Options>();
        //Add items to this shipping
        foreach (var item in DropDownOptions)
        {
            SelectListItem sliItem = new SelectListItem();
            string optionText = item._name;
            sliItem.Value = item._value.ToString();
            sliItem.Text = optionText;
            SelectedOptions.Add(sliItem);
        }
        ViewData["Option"] = SelectedOptions;

and in the view you can simply use

 @Html.DropDownList("Option", ViewData["Option"] as SelectList)

while submitting the form if you are using the class, do remember to put a string property with the name option in the class so that you can use it in the controller also the selected value when the form is submitted.

Answer 2

DropDownListFor takes a SelectList as a second argument while you are passing a List.

You could have something like the following:

@Html.DropDownListFor(m => m.selectedApplication, 
                     new SelectList(Model.Application,"Value","Text"))