What is the default value for enum variable?

Question

An enum variable, anyone know if it is always defaulting to the first element?

Answer 1

You can use this snippet :-D

using System;
using System.Reflection;

public static class EnumUtils
{
    public static T GetDefaultValue()
        where T : struct, Enum
    {
        return (T)GetDefaultValue(typeof(T));
    }

    public static object GetDefaultValue(Type enumType)
    {
        var attribute = enumType.GetCustomAttribute(inherit: false);
        if (attribute != null)
            return attribute.Value;

        var innerType = enumType.GetEnumUnderlyingType();
        var zero = Activator.CreateInstance(innerType);
        if (enumType.IsEnumDefined(zero))
            return zero;

        var values = enumType.GetEnumValues();
        return values.GetValue(0);
    }
}

Example:

using System;

public enum Enum1
{
    Foo,
    Bar,
    Baz,
    Quux
}
public enum Enum2
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 0
}
public enum Enum3
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 4
}
[DefaultValue(Enum4.Bar)]
public enum Enum4
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 4
}

public static class Program 
{
    public static void Main() 
    {
        var defaultValue1 = EnumUtils.GetDefaultValue();
        Console.WriteLine(defaultValue1); // Foo

        var defaultValue2 = EnumUtils.GetDefaultValue();
        Console.WriteLine(defaultValue2); // Quux

        var defaultValue3 = EnumUtils.GetDefaultValue();
        Console.WriteLine(defaultValue3); // Foo

        var defaultValue4 = EnumUtils.GetDefaultValue();
        Console.WriteLine(defaultValue4); // Bar
    }
}