Intrinsic and Custom Attributes

.NET framework is littered with attributes and CLR (common language runtime) provides a set of intrinsic attributes that are integrated into the framework. Serializable is an example of intrinsic attribute. Besides the framework supplied attributes, you can also define your own custom attributes to accomplish your goal.

When do you define your custom attributes? Attributes are suitable when you have crosscutting concerns. Object Oriented (OO) methodology lacks a modular approach to address crosscutting concerns in objects. Serialization is an example of crosscutting concern. Any object can be either serializable or non-serializable. If, for example, halfway in the development phase you realize that you need to make a few classes serializable, how do you do that? In .NET, you only need to mark them as serializable and provide methods to implement a serialization format. Other crosscutting concerns can be security, program monitoring and recording during debugging, data validation, etc. If you have a concern that affects a number of unrelated classes, you have a crosscutting concern and attributes are excellent candidates to address crosscutting concerns.