C# in a Nutshell, Second Edition

Name

Assembly

Synopsis

In the .NET environment, assemblies are the fundamental units of development and deployment; although the various languages allow the .NET programmer to work with elements as fine-grained as classes or functions, these types must belong as part of an assembly in order to be loaded and used. Consequently, the assembly is the core of the component model in .NET.

The Assembly type is the Reflection API object representing the assembly. An assembly (either a .DLL or .EXE—to the CLR, there is no difference) consists of one or more modules; most assemblies are in fact single-module assemblies. (Multimodule assemblies are certainly possible, but usually not necessary for most developers’ needs. As such, they are not discussed here.) .NET programmers can use the object model in the Assembly class to discover information about a particular assembly—for example, an assembly knows the modules contained within it, and each module knows the types defined and bound to that module. Thus, for any random assembly, a .NET program can enumerate each type defined inside that assembly. This is, in fact, what the WinCV.exe sample program (see the .NET SDK, in the \bin subdirectory) does. (The ILDasm.exe application provides similar results, but uses unmanaged APIs to view into an assembly, rather than Reflection.)

The Assembly API can be broken into two collections: those representing operations against a particular assembly (indicated by a particular Assembly instance), and those ...