Html.EnumDropdownListFor: Showing a default text

Question

In my view I have a enumdropdownlist (a new feature in Asp.Net MVC 5.1).

@Html.EnumDropDownListFor(m => m.SelectedLicense,new { @class="form-control"})

If I execute the above code I get dropdownlist for my following enum.

public enum LicenseTypes
{
    Trial = 0,
    Paid = 1
}

but by default I want my dropdownlist to have a value(custom text) and this is what I tried

@Html.EnumDropDownListFor(m => m.SelectedLicense,"Select a license" ,new { @class="form-control"})

but now the problem is when i run it, my dropdownlist looks like this So, the default text I want to show doesn't appear by default. If a user selects "select a license" and tries to submit the form, it does show an error saying "select a license" but it doesn't show as default text. Something i need to change?

Ps: The image is the screenshot of the page when it loads. By default it'll show Trial as selected option.

Answer 1

Try to change the Index of LicenseTypes start from 1 not 0 like below:

public enum LicenseTypes
{
    Trial = 1,
    Paid = 2
}

Then you can use Range attribute to validate the selected license type like below:

public class YourViewModel
{
     //Other properties
     [Range(1,int.MaxValue,ErrorMessage = "Select a correct license")]
     public LicenseTypes LicenseTypes { get; set; }
}

Finally, in your view:

   @Html.EnumDropDownListFor(m => m.LicenseTypes,"Select a license",new { @class = "form-control"})
   @Html.ValidationMessageFor(m => m.LicenseTypes)

Answer 2

By the time your EnumDropDownListFor is rendered SelectedLicense already has the default value for the type, which is 0.

Just change the type of your SelectedLicense property to a nullable enum, like so:

public LicenseTypes? SelectedLicense { get; set; }

This also allows you to continue using the Required attribute, which I think is significantly cleaner. The Required attribute will not allow a null response, so even though your model allows nulls, the form will not.

Answer 3

I have an enum:

public enum Sex
{
    Male,
    Female
}

In my model I have:

    [DisplayName("Sex")]
    [Required]
    public Sex? Sex { get; set; }

An in the view:

    @Html.EnumDropDownListFor(model => model.Sex, "Select sex", new { @class = "form-control", type = "text"})

By this I have a dropdown with default option "Select sex", but validation accepts only options provided by enum ("Male" and "Female").

In MVC3 (without EnumDropDownListFor) I used in model:

    [DisplayName("Sex")]
    [Required(AllowEmptyStrings=false)]
    public Sex? Sex { get; set; }

    Sex = null;

    Sexes = Repository.GetAutoSelectList<Sex>("");

In view:

    @Html.DropDownListFor(model => model.Sex, Model.Sexes, new { @class = "form-control", type = "text" })

Answer 4

The ViewModel class needs to have the default value set on the enum property for it to be the default selected public

public class Test
    {
        public Cars MyCars { get; set; }
        public enum Cars
        {
            [Display(Name = @"Car #1")]
            Car1 = 1,
            [Display(Name = @"Car #2")]
            Car2 = 2,
            [Display(Name = @"Car #3")]
            Car3 = 3
        }

    }

Controller:

 public class EnumController : Controller
    {
        // GET: Enum
        public ActionResult Index()
        {
            var model = new Test {MyCars = Test.Cars.Car3}; // set default value
            return View(model);
        }
        [HttpPost]
        public ActionResult Index(Test model)
        {
            .....
        }
    }

View:

@Html.BeginForm()
{
<div class="panel bg-white">
    <div class="panel-header fg-white">
        Enums
    </div>
    <div class="panel-content">
        <div class="input-control select size3">
            @Html.EnumDropDownListFor(model => model.MyCars)

        </div>
    </div>
    <input type="submit" class="button success large" />
</div>
}