C# enum contains value

Question

I have an enum

enum myEnum2 { ab, st, top, under, below}

I would like to write a function to test if a given value is included in myEnum

Answer 1

If your question is like "I have an enum type, enum MyEnum { OneEnumMember, OtherEnumMember }, and I'd like to have a function which tells whether this enum type contains a member with a specific name, then what you're looking for is the System.Enum.IsDefined method:

Enum.IsDefined(typeof(MyEnum), MyEnum.OneEnumMember); //returns true
Enum.IsDefined(typeof(MyEnum), "OtherEnumMember"); //returns true
Enum.IsDefined(typeof(MyEnum), "SomethingDifferent"); //returns false

If your question is like "I have an instance of an enum type, which has Flags attribute, and I'd like to have a function which tells whether this instance contains a specific enum value, then the function looks something like this:

public static bool ContainsValue(this TEnum e, TEnum val) where Enum: struct, IComparable, IFormattable, IConvertible
{
    if (!e.GetType().IsEnum)
        throw new ArgumentException("The type TEnum must be an enum type.", nameof(TEnum));

    dynamic val1 = e, val2 = val;
    return (val1 | val2) == val1;
}

Hope I could help.