Chapter 18. Reflection and Metadata

As we saw in the previous chapter, a C# program compiles into an assembly that includes metadata, compiled code, and resources. Inspecting the metadata and compiled code at runtime is called reflection.

The compiled code in an assembly contains almost all of the content of the original source code. Some information is lost, such as local variable names, comments, and preprocessor statements. However, reflection can access pretty much everything else, even making it possible to write a decompiler.

Many of the services available in .NET and exposed via C# (such as dynamic binding, serialization, data binding, and Remoting) depend on the presence of metadata. Your own programs can also take advantage of this metadata, and even extend it with new information using custom attributes. The System.Reflection namespace houses the reflection API. It is also possible at runtime to dynamically create new metadata and executable instructions in IL (Intermediate Language) via the classes in the System.Reflection.Emit namespace.

The examples in this chapter assume that you import the System and System.Reflection, as well as System.Reflection.Emit namespaces.


When we use the term “dynamically” in this chapter, we mean using reflection to perform some task whose type safety is enforced only at runtime. This is similar in principle to dynamic binding via C#’s dynamic keyword, although the mechanism and functionality is different.

To compare the two, dynamic binding ...

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