How to convert from a string to a Flags enum format in C#

Question

I have this enum:

[Flags]
public enum Countries
{
    None    = 0,
    USA     = 1,
    Mexico  = 2,
    Canada  = 4,
    Brazil  = 8,
    Chile   = 16
}

I receive in input strings like these:

string selectedCountries = "Usa, Brazil, Chile";

how to convert it (in C#) back to:

var myCountries = Countries.Usa | Countries.Brazil | Countries.Chile;

Nope I can't, I just receive strings formatted like that which is the default way flags enum are saved into strings. — Paul_T, Oct 29 '16 at 11:16
Shouldn't it be `string selectedCountries = "Usa, Brazil, Chile";`? — Maor Veitsman, Oct 29 '16 at 11:18

score 9 · Accepted Answer · answered Oct 29 '16 at 11:29

9

Use Enum.Parse.

e.g. Countries c = (Countries)Enum.Parse(typeof(Countries), "Usa, Brazil...");

answered Oct 29 '16 at 11:29

tyranid

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I agree it should Enum.Parse but don't think you can pass in the whole string directly into Enum.Parse. – dragonfly02 Oct 29 '16 at 11:36
Yes you can I just tested it. You are actually converting that string into a number and then casting it to enum. Thanks Tyranid – Paul_T Oct 29 '16 at 11:41
@Paul_T are you saing you can pass the string `Usa, Brazil` directly into `Enum.Parse` and it works? – dragonfly02 Oct 29 '16 at 11:43
That's correct stt106: if you pass the string "Usa, Brazil, Chile" to the Enum.parse it will work. After this call Countries c = (Countries)Enum.Parse(typeof(Countries), "Usa, Brazil..."); c stores Countries.Usa | Countries.Brazil | Countries.Chile – Paul_T Oct 29 '16 at 11:53
If you want to avoid possible exception use Enum.TryParse("Usa, Brazil", out Countries c) – Pavel Popov Apr 07 '22 at 12:06

score 3 · Answer 2 · answered Oct 29 '16 at 11:42

This seems to work for me assuming your country string is separated by a comma:

private static Countries ConvertToCountryEnum(string country)
        {
            return country.Split(',').Aggregate(Countries.None, (seed, c) => (Countries)Enum.Parse(typeof(Countries), c, true) | seed);
        }

score 0 · Answer 3 · edited Oct 29 '16 at 11:26

0

Actually I realized that it is easier than what i thought. All I need to do is convert that string into an int, in my case, or a long in general, and cast it to Countries. It will convert that number into the expected format. In other words:

(Countries) 25 = Countries.Usa | Countries.Brazil | Countries.Chile;

edited Oct 29 '16 at 11:26

Patrick Hofman

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answered Oct 29 '16 at 11:23

Paul_T

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That doesn't seem valid C#. – Patrick Hofman Oct 29 '16 at 11:26
Ok Patrick what I meant is that casting an int with an enum equals the "or" of the bits. Usa + Brazil + Chile = 1 +8 +16 = 25 not as C# code though. – Paul_T Oct 29 '16 at 11:30

How to convert from a string to a Flags enum format in C#

3 Answers3