Value is in enum list

Question

I have a fairly basic question: How can I check if a given value is contained in a list of enum values?

For example, I have this enum:

public enum UserStatus
{
    Unverified,
    Active,
    Removed,
    Suspended,
    Banned
}

Now I want to check if status in (Unverified, Active)

I know this works:

bool ok = status == UserStatus.Unverified || status == UserStatus.Active;

But there has to be a more elegant way to write this.

The topic of this question is very similar, but that's dealing with flags enums, and this is not a flags enum.

What is the datatype of status variable?

Lav
– Lav

2011-03-16 03:08:15 +00:00
Commented Mar 16, 2011 at 3:08 — Lav
– Lav, Commented Mar 16, 2011 at 3:08
@Lav The variable status is of type UserStatus.

Ian Boyd
– Ian Boyd

2020-06-05 13:42:01 +00:00
Commented Jun 5, 2020 at 13:42 — Ian Boyd
– Ian Boyd, Commented Jun 5, 2020 at 13:42

Cheng Chen · Accepted Answer · 2014-03-21 02:47:03Z

86

Here is an extension method that helps a lot in a lot of circumstances.

public static class Ext
{
    public static bool In<T>(this T val, params T[] values) where T : struct
    {
        return values.Contains(val);
    }
}

Usage:

Console.WriteLine(1.In(2, 1, 3));
Console.WriteLine(1.In(2, 3));
Console.WriteLine(UserStatus.Active.In(UserStatus.Removed, UserStatus.Banned));

edited Mar 21, 2014 at 2:47

answered Mar 16, 2011 at 3:27

Cheng Chen

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4 Comments

Jerad Rose Over a year ago

Yes, this is exactly what I was looking for. Again, not sure why this isn't built-in, but at least it's possible. :) Thanks!

BlueStrat Over a year ago

Beautiful code... had no idea that the this type parameter of an extension method could be generic.

Rizan Zaky Over a year ago

.NET 4.0+ has a built-in function for this, Enum.HasFlag(Enum). In this example, you can use it like, bool ok = (UserStatus.Unverified | UserStatus.Active).HasFlag(status);. More here, stackoverflow.com/a/61389498/4294275

Eric G Over a year ago

Okay. I'm sorry. Really basic question. Where would this code belong?

Femaref · Accepted Answer · 2011-03-16 03:08:56Z

35

If it is a longer list of enums, you can use:

var allowed = new List<UserStatus> { UserStatus.Unverified, UserStatus.Active };
bool ok = allowed.Contains(status);

Otherwise there is no way around the long || predicate, checking for each allowed value.

answered Mar 16, 2011 at 3:08

Femaref

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Comments

Jack · Accepted Answer · 2012-09-20 14:10:21Z

9

Use Enum.IsDefined

example:

public enum enStage {Work, Payment, Record, Return, Reject};
int StageValue = 4;

Enum.IsDefined(typeof(enStage), StageValue)

edited Sep 20, 2012 at 14:10

Jack

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answered Sep 20, 2012 at 14:04

Kiran Mahale

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1 Comment

Paul McCarthy Over a year ago

Can't see how this checks against 2 out of 5 values

Etienne de Martel · Accepted Answer · 2024-05-04 22:07:55Z

3

While that wasn't possible when the question was first asked, since C# 9 you can express that in a much more concise way, thanks to pattern matching with the is operator:

bool ok = status is UserStatus.Unverified or UserStatus.Active;

answered May 4, 2024 at 22:07

Etienne de Martel

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Comments

Martin Schneider · Accepted Answer · 2025-01-08 13:49:32Z

2

You can do this in .NET 4.0+ using Enum.HasFlag(Enum) method,

UserStatus status = UserStatus.Unverified; // just assumed status is Unverified

bool ok = (UserStatus.Unverified | UserStatus.Active).HasFlag(status);

You can also do the same by assigning into a variable like,

UserStatus status = UserStatus.Active; // just assumed status is Active

UserStatus unverifiedOrActive = UserStatus.Unverified | UserStatus.Active;

bool ok = unverifiedOrActive.HasFlag(status);

edited Jan 8 at 13:49

Martin Schneider

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answered Apr 23, 2020 at 14:21

Rizan Zaky

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2 Comments

RhinoDevel Over a year ago

This only works, if the enum values are actually flags (1, 2, 4, 8, 16, 32, 64, ...).

Martin Schneider Jan 8 at 13:55

I rolled back to the original answer as it 1) fundamentally changed its meaning, 2) was a copy of another user's answer that was posted 2 days earlier, 3) might still give value to some people that are looking for different approaches.

George Stocker · Accepted Answer · 2016-10-12 14:48:52Z

1

Why not create a method to encapsulate it?

public bool UnVerifiedOrActive(User user)
{
    return (user.UserStatus == UserStatus.Unverified || 
            user.UserStatus == UserStatus.Active);
}

edited Oct 12, 2016 at 14:48

answered Mar 16, 2011 at 3:08

George Stocker

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1 Comment

Jerad Rose Over a year ago

Thanks, but this isn't really a matter of DRY, just more about concise code. I'm still not sure why C# doesn't have some sort of in operator that can be used for cases like this.

Serj Sagan · Accepted Answer · 2024-05-04 21:16:58Z

-1

UserStatus userStatus = null;
Enum.TryParse<UserStatus>(status.ToString(), out userStatus);

if (userStatus != null)
{
  //it is not in the list
}

edited May 4, 2024 at 21:16

Serj Sagan

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answered Mar 16, 2011 at 3:12

Aivan Monceller

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6 Comments

Jerad Rose Over a year ago

I don't think this will work, as it is checking against every value in the enum, rather than a subset of values (if I'm reading correctly).

Aivan Monceller Over a year ago

@Jerad this works. give it a try. I have the same solution as what Lav posted

Jerad Rose Over a year ago

@Avian - but where do you check for just Unverified or Active values (vs. the other three values)?

Aivan Monceller Over a year ago

@Jerad. my bad. answering questions from the office didn't give me much time reading your question.

Jerad Rose Over a year ago

@Avian - I understand, no problem. Thanks for the attempt nonetheless.

|

Lav · Accepted Answer · 2011-03-16 03:11:48Z

-2

You can try following

UserStatus ustatus;
if(Enum.TryParse<UserStatus>(c.ToString(), out ustatus))
{
 ..Your logic
}

answered Mar 16, 2011 at 3:11

Lav

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1 Comment

Serj Sagan Over a year ago

Tested, this doesn't work to determine whether it has a value or not. Enum.TryParse is still true for values not in enum.

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