C# Explicit Type Casting Enumeration

Question

I need to create a List of object of whatever Enumeration type is passed into the function below. I don't know what type it will be, but it can be any one of many possible enumerations in my project.

public static List<object> CreateEnumList(Enum enumeration)
{ 
    List<object> returnList = new List<object>();
    for (int enumIndex = 0; enumIndex < Enum.GetNames(enumeration.GetType()).Length; enumIndex++)
        returnList.Add((enumeration.GetType())enumIndex);
    return returnList;
}

How can I get the type cast to work correctly? The return value MUST be List of objects. Thank you

What exactly is it that you want to add to your return list? In the code you've got, you're just trying to add the current iteration number to the list. — Filip Ekberg, Jul 03 '12 at 13:17
What do you mean? I need to create an instance of a class whose constructor takes that List — parliament, Jul 03 '12 at 13:18
Filip, I want to iterate through all the possible enumeration values and add them to a list. So something like returnList.Add((OnePossibleEnumeration)enumIndex); If I knew the exact enumeration type coming in I can simple case like that but I want it to work for all enumerations — parliament, Jul 03 '12 at 13:20

Nikhil Agrawal · Accepted Answer · 2012-07-03T13:23:11.563

6

This is enough

public static List<object> CreateEnumList(Enum enumeration)
{ 
    return Enum.GetValues(enumeration.GetType()).Cast<object>().ToList();
}

edited Jul 03 '12 at 13:23

answered Jul 03 '12 at 13:17

Nikhil Agrawal

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2

No. you need `enumeration.GetType()` – Eren Ersönmez Jul 03 '12 at 13:22
1

The usage is a little odd, you have to pass a member of the enum rather than the enum itself. Works though. – Jodrell Jul 03 '12 at 13:44

score 3 · Answer 2 · edited May 23 '17 at 12:20

Solution 1

Generic Enum to List converter (C#) One for the utility library...

It takes an enum type and returns a generic list populated with each enum item.

public static List<T> EnumToList<T>()
{
    Type enumType = typeof (T);

    // Can't use type constraints on value types, so have to do check like this
    if (enumType.BaseType != typeof(Enum))
        throw new ArgumentException("T must be of type System.Enum");

    Array enumValArray = Enum.GetValues(enumType);

    List<T> enumValList = new List<T>(enumValArray.Length);

    foreach (int val in enumValArray) {
        enumValList.Add((T)Enum.Parse(enumType, val.ToString()));
    }

    return enumValList;
}

Solution 2

This will return an IEnumerable<SomeEnum> of all the values of an Enum.

Enum.GetValues(typeof(SomeEnum)).Cast<SomeEnum>();

If you want that to be a List<SomeEnum>, just add .ToList() after .Cast<SomeEnum>().

public static List<T> CreateEnumList<T>(Enum enumeration)  
{
    return Enum.GetValues(typeof(T)).Cast<T>().ToList();
}

Check here : How do I convert an enum to a list in C#?

He said "The return value MUST be List of objects." Otherwise, I'd recommend this solution over the others, because it's strongly typed. — Tim S., Jul 03 '12 at 13:23

score 1 · Answer 3 · answered Jul 03 '12 at 13:18

Enum.Parse will do exactly what you need:

returnList.Add(Enum.Parse(enumeration.GetType(), enumIndex.ToString()));

For example, this prints b:

enum myEnum { a, b, c }
static void Main(string[] args)
{
    var e = Enum.Parse(typeof(myEnum), "1");
    Console.WriteLine(e);
}

score 0 · Answer 4 · answered Jul 03 '12 at 13:29

How about

public IList<object> GetBoxedEnumValues<TEnum>()
{
    Type enumType = typeOf(TEnum);

    if (!enumType.IsEnum)
    {
        throw new NotSupportedException(
            string.Format("\"{0}\" is not an Enum", enumType.Name));
    }

    return Enum.GetValues(enumType).Cast<object>().ToList();      
}

C# Explicit Type Casting Enumeration

4 Answers4