public enum Foos
{
A,
B,
C
}
Is there a way to loop through the possible values of Foos?
Basically?
foreach(Foo in Foos)
8 Answers
Yes you can use the GetValues method:
var values = Enum.GetValues(typeof(Foos));
Or the typed version:
var values = Enum.GetValues(typeof(Foos)).Cast<Foos>();
I long ago added a helper function to my private library for just such an occasion:
public static class EnumUtil {
public static IEnumerable<T> GetValues<T>() {
return Enum.GetValues(typeof(T)).Cast<T>();
}
}
Usage:
var values = EnumUtil.GetValues<Foos>();
16 Comments
Şafak Gür
You can cast the array directly:
(T[])Enum.GetValues(typeof(T))
Jeppe Stig Nielsen
The good thing about @ŞafakGür's comment is that (1) you don't have to go through an extra iterator (
.Cast<Foos>), and (2) you don't need to box all the values and unbox them again. Şafak's cast will remain valid as long as they don't change the array type returned to some other type (like object[]). But we can be completely sure they won't because (a) it would lose performance, (b) there are already millions of codelines using Şafak's cast, and they would all break with a runtime exception.
Jon Coombs
Of course, how many enums are going to contain more than a dozen or two values? I imagine that in most cases boxing/unboxing is a negligible hit, so the cleanest solution is the highest priority.
Şafak Gür
@JCoombs I find this clean enough:
public static IReadOnlyList<T> GetValues<T>() { return (T[])Enum.GetValues(typeof(T)); }. But yeah, performance difference is negligible in common usage. I just don't like the idea of creating an iterator when I already have an iterable (enumerable) object to return.
JAB
Unfortunately, this does not answer the question posed. The question was how to loop through the values of an enum. SLaks answered the question.
|
foreach(Foos foo in Enum.GetValues(typeof(Foos)))
5 Comments
Robert Patterson
This is a great solution. By using "Foos" instead of "var" the type inference system was able to use the right version of GetValues which returned the correct object type. Nice!
chtenb
@RobertPatterson By using
Foos nothing is magically inferred. It is an explicit cast.
Sinjai
@daveD I'd like to think people can handle writing a foreach block on their own.
silvalli
@RobertPatterson var works here, in 2019.
Ahmed Gamal
that is very good
foreach (EMyEnum val in Enum.GetValues(typeof(EMyEnum)))
{
Console.WriteLine(val);
}
Credit to Jon Skeet here: http://bytes.com/groups/net-c/266447-how-loop-each-items-enum
Comments
foreach (Foos foo in Enum.GetValues(typeof(Foos)))
{
...
}
1 Comment
R.Akhlaghi
Repeative answer dear @arian
UPDATED
Some time on, I see a comment that brings me back to my old answer, and I think I'd do it differently now. These days I'd write:
private static IEnumerable<T> GetEnumValues<T>()
{
// Can't use type constraints on value types, so have to do check like this
if (typeof(T).BaseType != typeof(Enum))
{
throw new ArgumentException("T must be of type System.Enum");
}
return Enum.GetValues(typeof(T)).Cast<T>();
}
5 Comments
Sebastian
Why is using LINQ "more correct"? Please c.f.
You can cast the array directly: (T[])Enum.GetValues(typeof(T)) @SafakGür, this version has less overhead IMO.
Saboor Awan
make it simple GetEnumValues<T>() where T : Enum
Carlos Muñoz
@SaboorAwan is not possible to use System.Enum as a type parameter constraint. Compiler says:
Constraint cannot be special class 'Enum'
Neil Barnwell
Yes that's why I have that comment and type checking thing in my implementation; I'd already thought of that. :)
WBuck
Quick note. In C# 7.3 you can now use
Enum (as well as unmanaged and delegate) as generic constraints.static void Main(string[] args)
{
foreach (int value in Enum.GetValues(typeof(DaysOfWeek)))
{
Console.WriteLine(((DaysOfWeek)value).ToString());
}
foreach (string value in Enum.GetNames(typeof(DaysOfWeek)))
{
Console.WriteLine(value);
}
Console.ReadLine();
}
public enum DaysOfWeek
{
monday,
tuesday,
wednesday
}
1 Comment
Yes. Use GetValues() method in System.Enum class.
1 Comment
stoj
And if you're using .net5, it comes with a generic version out of the box. i.e. no more typeof() and casting required as per most of the above examples. stackoverflow.com/a/65103244/227110
Enum.GetValues(typeof(Foos))
var values = Enum.GetValues<Foos>();