Attribute (computing)

In computing, an attribute is a specification that defines a property of an object, element, or file. It may also refer to or set the specific value for a given instance of such. For clarity, attributes should more correctly be considered metadata. An attribute is frequently and generally a property of a property. However, in actual usage, the term attribute can and is often treated as equivalent to a property depending on the technology being discussed. An attribute of an object usually consists of a name and a value; of an element, a type or class name; of a file, a name and extension.

For example, in computer graphics, line objects can have attributes such as thickness (with real values), color (with descriptive values such as brown or green or values defined in a certain color model, such as RGB), dashing attributes, etc. A circle object can be defined in similar attributes plus an origin and radius.

In the C# programming language, attributes are metadata attached to a field or a block of code like assemblies, members and types, and are equivalent to annotations in Java. Attributes are accessible to both the compiler and programmatically through reflection.

Users of the language see many examples where attributes are used to address cross-cutting concerns and other mechanistic or platform uses. This creates the false impression that this is their sole intended purpose. With attributes, it is possible to extend attributes such as abstract, sealed, or public.

Their specific use as metadata is left to the developer and can cover a wide range of types of information about any given application, classes and members that is not instance-specific. The decision to expose any given attribute as a property is also left to the developer as is the decision to use them as part of a larger application framework.

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