MVC3 Razor DropDownListFor Enums

プロジェクトをMVC3に更新しようとしていますが、これは見つかりません。

私はENUMSの単純なデータ型を持っています：

public enum States()
{
  AL,AK,AZ,...WY
}

Which I want to use as a DropDown/SelectList in my view of a model that contains this datatype:

public class FormModel()
{
    public States State {get; set;}
}

Pretty straight forward: when I go to use the auto-generate view for this partial class, it ignores this type.

I need a simple select list that sets the value of the enum as the selected item when I hit submit and process via my AJAX - JSON POST Method.

And than the view (???!):

    <div class="editor-field">
        @Html.DropDownListFor(model => model.State, model => model.States)
    </div>

thanks in advance for the advice!

I've just made one for my own project. The code below is part of my helper class, I hope that I got all methods needed. Write a comment if it doesn't work, and I'll check again.

public static class SelectExtensions
{

    public static string GetInputName<TModel, TProperty>(Expression<Func<TModel, TProperty>> expression)
    {
        if (expression.Body.NodeType == ExpressionType.Call)
        {
            MethodCallExpression methodCallExpression = (MethodCallExpression)expression.Body;
            string name = GetInputName(methodCallExpression);
            return name.Substring(expression.Parameters[0].Name.Length + 1);

        }
        return expression.Body.ToString().Substring(expression.Parameters[0].Name.Length + 1);
    }

    private static string GetInputName(MethodCallExpression expression)
    {
        // p => p.Foo.Bar().Baz.ToString() => p.Foo OR throw...
        MethodCallExpression methodCallExpression = expression.Object as MethodCallExpression;
        if (methodCallExpression != null)
        {
            return GetInputName(methodCallExpression);
        }
        return expression.Object.ToString();
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) where TModel : class
    {
        string inputName = GetInputName(expression);
        var value = htmlHelper.ViewData.Model == null
            ? default(TProperty)
            : expression.Compile()(htmlHelper.ViewData.Model);

        return htmlHelper.DropDownList(inputName, ToSelectList(typeof(TProperty), value.ToString()));
    }

    public static SelectList ToSelectList(Type enumType, string selectedItem)
    {
        List<SelectListItem> items = new List<SelectListItem>();
        foreach (var item in Enum.GetValues(enumType))
        {
            FieldInfo fi = enumType.GetField(item.ToString());
            var attribute = fi.GetCustomAttributes(typeof(DescriptionAttribute), true).FirstOrDefault();
            var title = attribute == null ? item.ToString() : ((DescriptionAttribute)attribute).Description;
            var listItem = new SelectListItem
                {
                    Value = ((int)item).ToString(),
                    Text = title,
                    Selected = selectedItem == ((int)item).ToString()
                };
            items.Add(listItem);
        }

        return new SelectList(items, "Value", "Text", selectedItem);
    }
}

Use it as:

Html.EnumDropDownListFor(m => m.YourEnum);

Update

I've created alternative Html Helpers. All you need to do to use them is to change your baseviewpage in views\web.config.

With them you can just do:

@Html2.DropDownFor(m => m.YourEnum);
@Html2.CheckboxesFor(m => m.YourEnum);
@Html2.RadioButtonsFor(m => m.YourEnum);

More info here: http://blog.gauffin.org/2011/10/first-draft-of-my-alternative-html-helpers/

I found a way simpler solution for this here: http://coding-in.net/asp-net-mvc-3-method-extension/

using System;
using System.Linq.Expressions;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Html;

namespace EnumHtmlHelper.Helper
{    
    public static class EnumDropDownList
    {
        public static HtmlString EnumDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> modelExpression, string firstElement)
        {
            var typeOfProperty = modelExpression.ReturnType;
            if(!typeOfProperty.IsEnum)
                throw new ArgumentException(string.Format("Type {0} is not an enum", typeOfProperty));     
            var enumValues = new SelectList(Enum.GetValues(typeOfProperty));
            return htmlHelper.DropDownListFor(modelExpression, enumValues, firstElement);
}   }   }

One line in razor will do it:

@Html.DropDownListFor(model => model.State, new SelectList(Enum.GetValues(typeof(MyNamespace.Enums.States))))

You can also find code for doing it with an extension method in the linked article.

As of ASP.NET MVC 5.1 (RC1), EnumDropDownListFor is included by default as an extension method of HtmlHelper.

If you want something really simple then there's another way, depending on how you store the state in the database.

If you had an entity like this:

public class Address
{
     //other address fields

     //this is what the state gets stored as in the db
     public byte StateCode { get; set; }

     //this maps our db field to an enum
     public States State
     {
         get
         {
             return (States)StateCode;
         }
         set
         {
             StateCode = (byte)value;
         }
     }
}

Then generating the dropdown would be as easy as this:

@Html.DropDownListFor(x => x.StateCode,
    from State state in Enum.GetValues(typeof(States))
    select new SelectListItem() { Text = state.ToString(), Value = ((int)state).ToString() }
);

Isn't LINQ pretty?

I was able to do this in a one liner.

@Html.DropDownListFor(m=>m.YourModelProperty,new SelectList(Enum.GetValues(typeof(YourEnumType))))

Based on the accepted answer by @jgauffin, I've created my own version of EnumDropDownListFor, which deals with the problem of selecting items.

The problem is detailed in another SO answer here:, and is basically down to a misunderstanding of the behaviour of the different overloads of DropDownList.

My full code (which includes overloads for htmlAttributes etc is:

public static class EnumDropDownListForHelper
{

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression
        ) where TModel : class
    {
        return EnumDropDownListFor<TModel, TProperty>(
                            htmlHelper, expression, null, null);
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression, 
            object htmlAttributes
        ) where TModel : class
    {
        return EnumDropDownListFor<TModel, TProperty>(
                            htmlHelper, expression, null, htmlAttributes);
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression, 
            IDictionary<string, object> htmlAttributes
        ) where TModel : class
    {
        return EnumDropDownListFor<TModel, TProperty>(
                            htmlHelper, expression, null, htmlAttributes);
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression, 
            string optionLabel
        ) where TModel : class
    {
        return EnumDropDownListFor<TModel, TProperty>(
                            htmlHelper, expression, optionLabel, null);
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression, 
            string optionLabel, 
            IDictionary<string,object> htmlAttributes
        ) where TModel : class
    {
        string inputName = GetInputName(expression);
        return htmlHelper.DropDownList(
                            inputName, ToSelectList(typeof(TProperty)), 
                            optionLabel, htmlAttributes);
    }

    public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(
            this HtmlHelper<TModel> htmlHelper, 
            Expression<Func<TModel, TProperty>> expression, 
            string optionLabel, 
            object htmlAttributes
        ) where TModel : class
    {
        string inputName = GetInputName(expression);
        return htmlHelper.DropDownList(
                            inputName, ToSelectList(typeof(TProperty)), 
                            optionLabel, htmlAttributes);
    }


    private static string GetInputName<TModel, TProperty>(
            Expression<Func<TModel, TProperty>> expression)
    {
        if (expression.Body.NodeType == ExpressionType.Call)
        {
            MethodCallExpression methodCallExpression 
                            = (MethodCallExpression)expression.Body;
            string name = GetInputName(methodCallExpression);
            return name.Substring(expression.Parameters[0].Name.Length + 1);

        }
        return expression.Body.ToString()
                    .Substring(expression.Parameters[0].Name.Length + 1);
    }

    private static string GetInputName(MethodCallExpression expression)
    {
        // p => p.Foo.Bar().Baz.ToString() => p.Foo OR throw...
        MethodCallExpression methodCallExpression 
                            = expression.Object as MethodCallExpression;
        if (methodCallExpression != null)
        {
            return GetInputName(methodCallExpression);
        }
        return expression.Object.ToString();
    }


    private static SelectList ToSelectList(Type enumType)
    {
        List<SelectListItem> items = new List<SelectListItem>();
        foreach (var item in Enum.GetValues(enumType))
        {
            FieldInfo fi = enumType.GetField(item.ToString());
            var attribute = fi.GetCustomAttributes(
                                       typeof(DescriptionAttribute), true)
                                  .FirstOrDefault();
            var title = attribute == null ? item.ToString() 
                              : ((DescriptionAttribute)attribute).Description;
            var listItem = new SelectListItem
            {
                Value = item.ToString(),
                Text = title,
            };
            items.Add(listItem);
        }

        return new SelectList(items, "Value", "Text");
    }
}

I've written this up on my blog here.

This would be helpful for selecting an int value from enum: Here SpecType is an int field... and enmSpecType is an enum.

@Html.DropDownList(
    "SpecType", 
     YourNameSpace.SelectExtensions.ToSelectList(typeof(NREticaret.Core.Enums.enmSpecType), 
     Model.SpecType.ToString()), "Tip Seçiniz", new 
     { 
         gtbfieldid = "33", 
         @class = "small" 
     })

I made the following change to the SelectList method to make it work a little better for me. Maybe it will be useful for others.

public static SelectList ToSelectList<T>(T selectedItem)
        {
            if (!typeof(T).IsEnum) throw new InvalidEnumArgumentException("The specified type is not an enum");

            var selectedItemName = Enum.GetName(typeof (T), selectedItem);
            var items = new List<SelectListItem>();
            foreach (var item in Enum.GetValues(typeof(T)))
            {
                var fi = typeof(T).GetField(item.ToString());
                var attribute = fi.GetCustomAttributes(typeof(DescriptionAttribute), true).FirstOrDefault();

                var enumName = Enum.GetName(typeof (T), item);
                var title = attribute == null ? enumName : ((DescriptionAttribute)attribute).Description;

                var listItem = new SelectListItem
                {
                    Value = enumName,
                    Text = title,
                    Selected = selectedItemName == enumName
                };
                items.Add(listItem);
            }

            return new SelectList(items, "Value", "Text");
        }

    public enum EnumStates
    {
        AL = 0,
        AK = 1,
        AZ = 2,
        WY = 3
    }


@Html.DropDownListFor(model => model.State, (from EnumStates e in Enum.GetValues(typeof(EnumStates))
                                                               select new SelectListItem { Value = ((int)e).ToString(), Text = e.ToString() }), "select", new { @style = "" })
                @Html.ValidationMessageFor(model => model.State)  //With select



//Or


@Html.DropDownListFor(model => model.State, (from EnumStates e in Enum.GetValues(typeof(EnumStates))
                                                               select new SelectListItem { Value = ((int)e).ToString(), Text = e.ToString() }), null, new { @style = "" })
                @Html.ValidationMessageFor(model => model.State)   //With out select

Same as Mike's (which is buried between lengthy responses)

model.truckimagelocation is class instance property of the TruckImageLocation enumeration type

@Html.DropDownListFor(model=>model.truckimagelocation,Enum.GetNames(typeof(TruckImageLocation)).ToArray().Select(f=> new SelectListItem() {Text = f, Value = f, Selected = false}))

This is most generic code which will be used for all Enums.

public static class UtilitiesClass
{

    public static SelectList GetEnumType(Type enumType)
    {
        var value = from e in Enum.GetNames(enumType)
                    select new
                    {
                        ID = Convert.ToInt32(Enum.Parse(enumType, e, true)),
                        Name = e
                    };
        return new SelectList(value, "ID", "Name");
    }
}

Action Method

ViewBag.Enum= UtilitiesClass.GetEnumType(typeof (YourEnumType));

View.cshtml

 @Html.DropDownList("Type", (IEnumerable<SelectListItem>)ViewBag.Enum, new { @class = "form-control"})

you can use enum in your model

your Enum

public enum States()
{
  AL,AK,AZ,...WY
}

make a model

public class enumclass
{
public States statesprop {get; set;}
}

in view

@Html.Dropdownlistfor(a=>a.statesprop)

The easiest answer in MVC5 is Define Enum:

public enum ReorderLevels {
          zero = 0,
            five = 5,
            ten = 10,
            fifteen = 15,
            twenty = 20,
            twenty_five = 25,
            thirty = 30
        }

Bind In View:

        <div class="form-group">
            <label>Reorder Level</label>
            @Html.EnumDropDownListFor(m => m.ReorderLevel, "Choose Me", new { @class = "form-control" })
        </div>