DescriptionAttribute.cs

namespace System.ComponentModel
{
    [AttributeUsage(AttributeTargets.All)]
    public class DescriptionAttribute : Attribute
    {
        public static readonly DescriptionAttribute Default = new DescriptionAttribute();

        private string description;

        public virtual string Description => DescriptionValue;

        protected string DescriptionValue
        {
            get
            {
                return description;
            }
            set
            {
                description = value;
            }
        }

        public DescriptionAttribute()
            : this(string.Empty)
        {
        }

        public DescriptionAttribute(string description)
        {
            this.description = description;
        }

        public override bool Equals(object obj)
        {
            if (obj == this)
            {
                return true;
            }
            DescriptionAttribute descriptionAttribute = obj as DescriptionAttribute;
            if (descriptionAttribute != null)
            {
                return descriptionAttribute.Description == Description;
            }
            return false;
        }

        public override int GetHashCode()
        {
            return Description.GetHashCode();
        }

        public override bool IsDefaultAttribute()
        {
            return Equals(Default);
        }
    }
}