Programming C# 5.0

Chapter 12. Assemblies

So far in this book, I’ve used the term component to describe either a library or an executable. It’s now time to look more closely at exactly what that means. In .NET the proper term for a software component is an assembly, and it is typically a .dll or .exe file. Occasionally, an assembly will be split into multiple files, but even then it is an indivisible unit of deployment—you must either make the whole assembly available to the CLR, or not deploy it at all. Assemblies are an important aspect of the type system, because each type is identified not just by its name and namespace, but also by its containing assembly. Assemblies provide a kind of encapsulation that operates at a larger scale than individual types, thanks to the internal accessibility specifier, which works at the assembly level.

The runtime provides an assembly loader, which automatically finds and loads the assemblies a program needs. To ensure that the loader can find the right components, assemblies have structured names that include version information, and they can optionally contain a globally unique element to prevent ambiguity.

Visual Studio and Assemblies

In Visual Studio, most of the project types under Visual C# in the New Project dialog produce a single assembly as their output. They will often put other files in the output folder too, such as copies of assemblies from outside of the .NET Framework class library that your project relies on, and other files needed by your application. ...