#469 – Attaching an Attribute to a Type Member

An attribute describes metadata that should be associated with a particular type member.

Below is an example of attaching the Obsolete attribute to the Cow.FeedCowInBarn method.  A developer can use this attribute to mark a method as being obsolete or deprecated, indicating that it should no longer be called.

You attach an attribute to a type member by using a square bracket followed by the name of the attribute and then any arguments that the attribute takes.  The Obsolete attribute takes a single argument that will be displayed at compile time when code tries to call the associated method.

        [Obsolete("Feeding cows indoors is no longer recommended.  Instead, call the LetGrazeOutside() method.")]
        public void FeedCowInBarn()
        {
            Console.WriteLine("Cow eats slop in dim confines of barn");
        }

Intellisense now tells us that the method is deprecated.

We also see the specified message at compile-time.