Attributes are language constructs that can decorate a code element (assemblies, modules, types, members, return values, and parameters) with additional information.
In every language, you specify information associated with the types,
methods, parameters, and other elements of your program. For example,
a type can specify a list of interfaces that it derives from, or a
parameter can specify how its values are to be passed with modifiers
such as the
ref modifier in C#. The limitation of
this approach is that you can only associate information with code
elements using the predefined constructs that the language itself
Attributes allow programmers to add to the types of information associated with these code elements. For example, serialization in the .NET Framework uses various serialization attributes applied to types and fields to define how these code elements are serialized. This is more flexible than requiring the language to have special syntax for serialization.
An attribute is defined by a class that inherits (directly or
indirectly) from the abstract class
. When specifying an attribute on an
element, the attribute name is the name of the type. By convention
the derived type name ends with the word “Attribute”, but
this suffix isn’t required.
In this example we specify that the