SerializableAttribute.cs

using System.Reflection;
using System.Runtime.InteropServices;

namespace System
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum | AttributeTargets.Delegate, Inherited = false)]
    [ComVisible(true)]
    public sealed class SerializableAttribute : Attribute
    {
        internal static Attribute GetCustomAttribute(RuntimeType type)
        {
            if ((type.Attributes & TypeAttributes.Serializable) != TypeAttributes.Serializable)
            {
                return null;
            }
            return new SerializableAttribute();
        }

        internal static bool IsDefined(RuntimeType type)
        {
            return type.IsSerializable;
        }
    }
}