使用enum和Entity Framework脚手架从模型创建下拉列表？

Question

Is there a way for Entity Framework to automatically create a dropdown list in HTML given that the model has an enum property? Here's what I currently have inside my model, but when running my project there's just a text box instead of a dropdown!

public enum MajorList { Accounting, BusinessHonors, Finance, InternationalBusiness, Management, MIS, Marketing, SupplyChainManagement, STM }
[Display(Name = "Major")]
[Required(ErrorMessage = "Please select your major.")]
[EnumDataType(typeof(MajorList))]
public MajorList Major { get; set; }

Answer 1

You could change your @Html.EditorFor for the following:

@Html.EnumDropDownListFor(model => model.Major, htmlAttributes: new { @class = "form-control" })

Update:

As @StephenMuecke confirmed in his comment EnumDropDownListFor is only available in MVC 5.1, so another solution could be getting the enum values using Enum.GetValues method. One option to pass that data to your View could be using the ViewBag :

var majorList = Enum.GetValues(typeof(MajorList))
                    .Cast<MajorList>()
                    .Select(e => new SelectListItem
                         {
                             Value =e.ToString(),
                             Text = e.ToString()
                         });
ViewBag.MajorList=majorList;

Or adding it as a property in your ViewModel in case you were working that way.

Later in your View you could use a DropDownList as follows:

@Html.DropDownListFor(model => model.Major, ViewBag.MajorList, htmlAttributes: new { @class = "form-control" })

According to the solution in this post the following also should work:

@Html.DropDownListFor(model =>model.Major, new SelectList(Enum.GetValues(typeof(MajorList))))

Another solution could be create your own EnumDropDownListFor helper (check this page if you want to read more about this kind of solution):

using System.Web.Mvc.Html;

public static class HTMLHelperExtensions
{
    public static MvcHtmlString EnumDropDownListFor<TModel, TEnum>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TEnum>> expression)
    {
        ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
        IEnumerable<TEnum> values = Enum.GetValues(typeof(TEnum)).Cast<TEnum>();

        IEnumerable<SelectListItem> items =
            values.Select(value => new SelectListItem
            {
                Text = value.ToString(),
                Value = value.ToString(),
                Selected = value.Equals(metadata.Model)
            });

        return htmlHelper.DropDownListFor(
            expression,
            items
            );
    }
}

This way you can do the same that I suggested at the beginning of my answer just you need to reference the namespace where you declare your static class with your extension:

@using yourNamespace 
//...

 @Html.EnumDropDownListFor(model => model.Major, htmlAttributes: new { @class = "form-control" })