Attributes and Reflection

Throughout this book, I have emphasized that a .NET application contains code, data, and metadata. Metadata is information about the data--that is, information about the types, code, assembly, and so forth--stored along with your program. This chapter explores how some
of that metadata is created and used.

Attributes are a mechanism for adding metadata, such as compiler instructions and other
data about your data, methods, and classes, to the program itself. Attributes are inserted
into the metadata and are visible through ILDasm and other metadata-reading tools.

Reflection is the process by which a program can read its own metadata. A program is
said to reflect on itself, extracting metadata from its assembly and using that metadata
either to inform the user or to modify its own behavior.