怎样给一个继承后的枚举添加成员？

类内或接口内定义的枚举继承后全部没办法再添加成员，除去特性和反射，还有什么好的方法么？

如果是这种情况，为什么不使用类呢？
像这样:

public class Base
{
    public const int A = 1;
    public const int B = 2;
    public const int C = 3;
}
public class Child : Base
{
    public const int D = 4;
    public const int E = 5;
}

或者

public class MyBaseEnum
{
    public static readonly MyBaseEnum A = new MyBaseEnum( 1 );
    public static readonly MyBaseEnum B = new MyBaseEnum( 2 );
    public static readonly MyBaseEnum C = new MyBaseEnum( 3 );

    public int InternalValue { get; protected set; }

    protected MyBaseEnum( int internalValue )
    {
        this.InternalValue = internalValue;
    }
}

public class MyEnum : MyBaseEnum
{
    public static readonly MyEnum D = new MyEnum( 4 );
    public static readonly MyEnum E = new MyEnum( 5 );

    protected MyEnum( int internalValue ) : base( internalValue )
    {
        // Nothing
    }
}

另外，你不应该在类或接口中定义枚举。