How to get the values of an enum into a SelectList

Question

Imagine I have an enumeration such as this (just as an example):

public enum Direction{
    Horizontal = 0,
    Vertical = 1,
    Diagonal = 2
}

How can I write a routine to get these values into a System.Web.Mvc.SelectList, given that the contents of the enumeration are subject to change in future? I want to get each enumerations name as the option text, and its value as the value text, like this:

<select>
    <option value="0">Horizontal</option>
    <option value="1">Vertical</option>
    <option value="2">Diagonal</option>
</select>

This is the best I can come up with so far:

 public static SelectList GetDirectionSelectList()
 {
    Array values = Enum.GetValues(typeof(Direction));
    List<ListItem> items = new List<ListItem>(values.Length);

    foreach (var i in values)
    {
        items.Add(new ListItem
        {
            Text = Enum.GetName(typeof(Direction), i),
            Value = i.ToString()
        });
    }

    return new SelectList(items);
 }

However this always renders the option text as 'System.Web.Mvc.ListItem'. Debugging through this also shows me that Enum.GetValues() is returning 'Horizontal, Vertical' etc. instead of 0, 1 as I would've expected, which makes me wonder what the difference is between Enum.GetName() and Enum.GetValue().

This is a big duplicate of http://stackoverflow.com/questions/1102022/display-enum-in-combobox-with-spaces and many, many others. — John Saunders, Jul 10 '09 at 15:11

Brandon · Answer 1 · 2011-03-02T21:25:08.160

96

It's been awhile since I've had to do this, but I think this should work.

var directions = from Direction d in Enum.GetValues(typeof(Direction))
           select new { ID = (int)d, Name = d.ToString() };
return new SelectList(directions , "ID", "Name", someSelectedValue);

edited Mar 02 '11 at 21:25

answered Jul 10 '09 at 15:08

Brandon

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5

Almost works, only needs a minor change! Your code will set the value to the Text when the OP wanted it to be an integer. Easy fix though. Change `ID = d` to `ID = (int)d`. Thanks for posting this, I never would have thought of it! – Christopher Apr 20 '10 at 06:06
Great answer, though I found that to pre-populate the dropdown, the value had to be the text representation of the enum, not the integer. – Luke Alderton Nov 25 '15 at 17:10

score 45 · Answer 2 · answered Mar 09 '15 at 10:44

45

There is a new feature in ASP.NET MVC 5.1 for this.

http://www.asp.net/mvc/overview/releases/mvc51-release-notes#Enum

@Html.EnumDropDownListFor(model => model.Direction)

answered Mar 09 '15 at 10:44

Fred

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Is there a `taghelper` version of this? – Serj Sagan Oct 25 '16 at 02:07
4

@SerjSagan, Yes. ``. – Fred Oct 25 '16 at 10:59
1

how do you get the selected value out in the controller form this? – Transformer Jan 09 '18 at 00:10

score 34 · Answer 3 · answered Feb 17 '10 at 15:35

34

This is what I have just made and personally I think its sexy:

 public static IEnumerable<SelectListItem> GetEnumSelectList<T>()
        {
            return (Enum.GetValues(typeof(T)).Cast<T>().Select(
                enu => new SelectListItem() { Text = enu.ToString(), Value = enu.ToString() })).ToList();
        }

I am going to do some translation stuff eventually so the Value = enu.ToString() will do a call out to something somewhere.

answered Feb 17 '10 at 15:35

Dan

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I'm having a problem with this code. The "Value" of the SelectList is the same as the "Text". When using Enums with EntityFramework, the value saved back to the database must be an int. – Northstrider Jul 12 '13 at 18:01
Ok, well do this then: Value = (int)enu – Dan Jul 15 '13 at 16:13
The reason (int)enu doesn't work in the example above is because the Value property of SelectListItem is a string not an integer. ((int)enu).ToString() will work. – Teppic Oct 17 '14 at 03:55
No it won't. In the example above, at compile time it doesn't know the type of `T`. As such, you can't cast to `int` like that. – ajbeaven Aug 17 '17 at 08:47
As from C# 7.3 you can now add 'where T : System.Enum'. – Johan Maes Jan 02 '19 at 10:06

score 28 · Accepted Answer · answered Jul 10 '09 at 15:08

28

To get the value of an enum you need to cast the enum to its underlying type:

Value = ((int)i).ToString();

answered Jul 10 '09 at 15:08

Andrew Hare

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635

Thanks! I thought about this but thought there might be a way to do it without casting. – Lee D Jul 10 '09 at 15:18

score 25 · Answer 5 · answered Apr 02 '13 at 16:08

25

I wanted to do something very similar to Dann's solution, but I needed the Value to be an int and the text to be the string representation of the Enum. This is what I came up with:

public static IEnumerable<SelectListItem> GetEnumSelectList<T>()
    {
        return (Enum.GetValues(typeof(T)).Cast<int>().Select(e => new SelectListItem() { Text = Enum.GetName(typeof(T), e), Value = e.ToString() })).ToList();
    }

answered Apr 02 '13 at 16:08

J.Noel.K

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1

This is by far the better answer. Value needed to be int representation of enum. – Fahad Abid Janjua Jul 25 '16 at 01:54

score 16 · Answer 6 · answered Oct 25 '16 at 11:03

16

In ASP.NET Core MVC this is done with tag helpers.

<select asp-items="Html.GetEnumSelectList<Direction>()"></select>

answered Oct 25 '16 at 11:03

Fred

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What about setting the selected one on load? – JordanGW Mar 20 '20 at 10:04
Then you need to specify the the `asp-for` attribute. – Fred Apr 20 '20 at 11:23

score 4 · Answer 7 · answered Jul 21 '09 at 08:50

maybe not an exact answer to the question, but in CRUD scenarios i usually implements something like this:

private void PopulateViewdata4Selectlists(ImportJob job)
{
   ViewData["Fetcher"] = from ImportFetcher d in Enum.GetValues(typeof(ImportFetcher))
                              select new SelectListItem
                              {
                                  Value = ((int)d).ToString(),
                                  Text = d.ToString(),
                                  Selected = job.Fetcher == d
                              };
}

PopulateViewdata4Selectlists is called before View("Create") and View("Edit"), then and in the View:

<%= Html.DropDownList("Fetcher") %>

and that's all..

score 4 · Answer 8 · answered Jul 23 '14 at 07:45

return
            Enum
            .GetNames(typeof(ReceptionNumberType))
            .Where(i => (ReceptionNumberType)(Enum.Parse(typeof(ReceptionNumberType), i.ToString())) < ReceptionNumberType.MCI)
            .Select(i => new
            {
                description = i,
                value = (Enum.Parse(typeof(ReceptionNumberType), i.ToString()))
            });

score 4 · Answer 9 · answered Jan 27 '12 at 15:43

4

Or:

foreach (string item in Enum.GetNames(typeof(MyEnum)))
{
    myDropDownList.Items.Add(new ListItem(item, ((int)((MyEnum)Enum.Parse(typeof(MyEnum), item))).ToString()));
}

answered Jan 27 '12 at 15:43

zkarolyi

41
1

score 3 · Answer 10 · answered Jul 16 '13 at 16:09

    public static SelectList ToSelectList<TEnum>(this TEnum enumObj) where TEnum : struct
    {
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum e in Enum.GetValues(typeof(TEnum)) select new { ID = (int)Enum.Parse(typeof(TEnum), e.ToString()), Name = e.ToString() };
        //var values = from TEnum e in Enum.GetValues(typeof(TEnum)) select new { ID = e, Name = e.ToString() };

        return new SelectList(values, "ID", "Name", enumObj);
    }
    public static SelectList ToSelectList<TEnum>(this TEnum enumObj, string selectedValue) where TEnum : struct
    {
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum e in Enum.GetValues(typeof(TEnum)) select new { ID = (int)Enum.Parse(typeof(TEnum), e.ToString()), Name = e.ToString() };
        //var values = from TEnum e in Enum.GetValues(typeof(TEnum)) select new { ID = e, Name = e.ToString() };
        if (string.IsNullOrWhiteSpace(selectedValue))
        {
            return new SelectList(values, "ID", "Name", enumObj);
        }
        else
        {
            return new SelectList(values, "ID", "Name", selectedValue);
        }
    }

score 3 · Answer 11 · answered Jul 18 '15 at 07:37

I have more classes and methods for various reasons:

Enum to collection of items

public static class EnumHelper
{
    public static List<ItemDto> EnumToCollection<T>()
    {
        return (Enum.GetValues(typeof(T)).Cast<int>().Select(
            e => new ItemViewModel
                     {
                         IntKey = e,
                         Value = Enum.GetName(typeof(T), e)
                     })).ToList();
    }
}

Creating selectlist in Controller

int selectedValue = 1; // resolved from anywhere
ViewBag.Currency = new SelectList(EnumHelper.EnumToCollection<Currency>(), "Key", "Value", selectedValue);

MyView.cshtml

@Html.DropDownListFor(x => x.Currency, null, htmlAttributes: new { @class = "form-control" })

score 3 · Answer 12 · answered Apr 07 '17 at 08:30

I had many enum Selectlists and, after much hunting and sifting, found that making a generic helper worked best for me. It returns the index or descriptor as the Selectlist value, and the Description as the Selectlist text:

Enum:

public enum Your_Enum
{
    [Description("Description 1")]
    item_one,
    [Description("Description 2")]
    item_two
}

Helper:

public static class Selectlists
{
    public static SelectList EnumSelectlist<TEnum>(bool indexed = false) where TEnum : struct
    {
        return new SelectList(Enum.GetValues(typeof(TEnum)).Cast<TEnum>().Select(item => new SelectListItem
        {
            Text = GetEnumDescription(item as Enum),
            Value = indexed ? Convert.ToInt32(item).ToString() : item.ToString()
        }).ToList(), "Value", "Text");
    }

    // NOTE: returns Descriptor if there is no Description
    private static string GetEnumDescription(Enum value)
    {
        FieldInfo fi = value.GetType().GetField(value.ToString());
        DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
        if (attributes != null && attributes.Length > 0)
            return attributes[0].Description;
        else
            return value.ToString();
    }
}

Usage: Set parameter to 'true' for indices as value:

var descriptorsAsValue = Selectlists.EnumSelectlist<Your_Enum>();
var indicesAsValue = Selectlists.EnumSelectlist<Your_Enum>(true);

How to get the values of an enum into a SelectList

12 Answers12

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