.NET metadata

.NET Metadata
From Wikipedia, the free encyclopedia

.NET metadata refers to certain data structures embedded within the Common Intermediate Language code that describes the high-level structure of the code. Metadata describes all classes and class members that are defined in the assembly and all class that will be called for. The metadata for a method contains the complete description of the method, including the class, the return type and all of the method parameters.

A .NET language compiler will generate the metadata and store this in the assembly containing the CIL. When the CLR executes CIL it will check to make sure that the metadata of the called method is the same as the metadata that is stored in the calling method. This ensures that a method can only be called with exactly the right number of parameters and exactly the right parameter types.


Developers can add metadata to their code through attributes, custom and pseudo custom attributes.

A custom attribute is a regular class that inherits from the Attribute class. A custom attribute can be used on any method, property, class or entire assembly with the syntax: [Attribute name(optional parameter, optional name=value pairs)]

A pseudo-custom attribute is used just like regular custom attributes but they do not have a custom handler; rather the compiler has intrinsic awareness of the attributes and handles the code marked with such attributes differently.