How to set the default value for Html.DropDownListFor in MVC

Question

i have following code : controller method:

 public ActionResult Register(int? registrationTypeId)
        {
            IEnumerable<AccountType> accountTypes = new List<AccountType>
            {
                new AccountType
                {
                    AccountTypeId = 1,
                    AccountTypeName = "Red"
                },
                new AccountType
                {
                    AccountTypeId = 2,
                    AccountTypeName = "Blue"
                }
            };
           // I want to select account type on registrationTypeId
            ViewBag.AccountTypes = accountTypes;
            return View();
      }

View

<div class="col-md-10">
            @Html.DropDownListFor(n => n.AccountType,
         new SelectList(ViewBag.AccountTypes, "AccountTypeId", "AccountTypeName"), new { @class = "form-control" })
</div>

Model

public class RegisterViewModel
    { 
        [Required]
        [Display(Name = "Account Type")]
        public int AccountType { get; set; 
    }

As you can see registrationTypeId in controller , i want to set the type on its bases if it is not null ,otherwise set to red. I have tried a alot but nothing worked for me. Any help will be appreciated !

possible duplicate of [How can I get this ASP.NET MVC SelectList to work?](http://stackoverflow.com/questions/781987/how-can-i-get-this-asp-net-mvc-selectlist-to-work) — CodeCaster, Dec 04 '14 at 15:09
What do you mean by default? Do you mean you want to set the value? Or do you mean you want it to display something when there is nothing selected (ie.. "Select a value" or similar)? — Erik Funkenbusch, Dec 05 '14 at 11:34

score 1 · Accepted Answer · answered Dec 04 '14 at 15:37

1

I would highly recommend that you don't pass your list through the view bag. have seen too many questions where that has caused major issues. add this to your model

public List<SelectListItem> AccountTypes { get; set; }

in your controller in the get method set your default and set your list

Model.AccountType = 1;  // change the one to your default value
Model.AccountTypes = accountTypes;  //instead of ViewBag.AccountTypes = accountTypes;

then on your view

@Html.DropDownListFor(x => x.AccountType, Model.AccountTypes)

setting AccountType before passing the model to the view will set the default and the selected value on the view will be passed back in that same value.

answered Dec 04 '14 at 15:37

Matt Bodily

6,403
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Why are lists passed to the view in the ViewBag in examples and in the out of the box project? – Inspector Squirrel Dec 05 '14 at 09:45
my guess is it is a quick and dirty way to get it to work. passing the list through the model is much more stable and reliable. – Matt Bodily Dec 05 '14 at 16:47
Microsoft's examples are famous for not being very industry-proof and for often showing "worst practices" unfortunately... because they are trying to market the idea of "easy to code" so they want it to look as simple as possible on their website – nothingisnecessary Mar 01 '17 at 19:39

Inspector Squirrel · Answer 2 · 2014-12-05T09:48:45.077

0

The Wrong Way To Do This

var accountTypes = new SelectList(accountTypes, "AccountTypeId", "AccountTypeName");

foreach(var item in accountList)
    if (item.AccountTypeId == registrationTypeId)
        item.Selected = true;

ViewBag.AccountTypes = accountTypes;

In view,

@Html.DropDownListFor(n => n.AccountType, (SelectList)ViewBag.AccountTypes)

edited Dec 05 '14 at 09:48

answered Dec 04 '14 at 15:18

Inspector Squirrel

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You do not (and should not) do this. Setting the `item.Selected` property is ignored by the `@Html.DropDownListFor()` so its pointless. If the value of `AccountType` matches the value of one of the options, then that option will be selected. – Dec 04 '14 at 23:11
Didn't realise, never actually done it like this before. – Inspector Squirrel Dec 05 '14 at 09:43
1

I'll leave it up, your explanation might help people. – Inspector Squirrel Dec 05 '14 at 09:50

How to set the default value for Html.DropDownListFor in MVC

2 Answers2

The Wrong Way To Do This

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