MVC 4 Html.ListBoxFor Model MultiSelectList IEnumerable Error?

Posted on 2014-01-13
Last Modified: 2014-01-19
I have successfully using the Html.ListBox with a ViewData like so:

ViewData["GroupsList"] = new MultiSelectList(myGroups.GetAllGroups(), "GroupID", "GroupName");

@Html.ListBox("lbxGroups", (MultiSelectList)ViewData["GroupsList"], new { SelectionMode = "Single" })

Now I want to use the Model and having issues doing so.

I received this error when using Model.UserGroupList:

"The parameter 'expression' must evaluate to an IEnumerable when multiple selection is allowed."

Note: the Action returns the correct data.

public ActionResult Index()
       ManagerViewModel viewModel = new ManagerViewModel()
                UserGroupsList = new MultiSelectList(myGroups.GetAllGroups(), "GroupID", "GroupName")
            return View(viewModel);

@model ProjectUI.ManagerViewModel
@Html.ListBoxFor(model => model.GroupId, new MultiSelectList(Model.UserGroupsList, "Value", "Text"), new { SelectionMode = "Single" }))

public class ManagerViewModel
        public int GroupId { get; set; }
        public MultiSelectList UserGroupsList { get; set; }
Question by:WorknHardr
  • 3
LVL 16

Accepted Solution

Imran Javed Zia earned 500 total points
ID: 39778720

If you have single selection, then technically you may use dropdown. Please try following:

@Html.ListBoxFor(model => model.GroupId,
                new SelectList(Model.UserGroupsList, "Value", "Text"))

for more information, please refer to following:


Author Comment

ID: 39779504
Same error:
"The parameter 'expression' must evaluate to an IEnumerable when multiple selection is allowed."

Until.... I change the Action to SelectList from MultiSelectList like so:

     ManagerViewModel viewModel = new ManagerViewModel()
                UserGroupsList = new SelectList(myGroups.GetAllGroups(), "GroupID", "GroupName")

Q. Why do I find code snippets elsewhere using the MultiSelectList?

Author Comment

ID: 39779733
Just tried this example and get the same working result as your suggestion, without using a SelectList in the view.

View model:
public class MyViewModel
    public int[] SelectedIds { get; set; }
    public IEnumerable<SelectListItem> Items { get; set; }

public ActionResult Index()
    var model = new MyViewModel
        // fetch the items from some data source
        Items = Enumerable.Select(x => new SelectListItem
            Value = x.Id,
            Text = "item " + x.Id
    return View(model);

@model MyViewModel
@Html.ListBoxFor(x => x.SelectedIds, Model.Items)

Author Closing Comment

ID: 39792647

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Visual Studio: built-in keystroke automation 2 46
error on the page 1 33
Two different visual studio versions 3 21
Server Error 11 47
IntroductionWhile developing web applications, a single page might contain many regions and each region might contain many number of controls with the capability to perform  postback. Many times you might need to perform some action on an ASP.NET po…
Introduction This article shows how to use the open source plupload control to upload multiple images. The images are resized on the client side before uploading and the upload is done in chunks. Background I had to provide a way for user…
This tutorial demonstrates a quick way of adding group price to multiple Magento products.
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …

919 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now