C# 9.0 in a Nutshell

Chapter 17. Assemblies

An assembly is the basic unit of deployment in .NET and is also the container for all types. An assembly contains compiled types with their Intermediate Language (IL) code, runtime resources, and information to assist with versioning and referencing other assemblies. An assembly also defines a boundary for type resolution. In .NET, an assembly comprises a single file with a .dll extension.

Note

When you build an executable application in .NET, you end up with two files: an assembly (.dll) and an executable launcher (.exe) appropriate to the platform you’re targeting.

This differs from what happens in .NET Framework, which generates a portable executable (PE) assembly. A PE has an .exe extension and acts both as an assembly and an application launcher. A PE can simultaneously target 32- and 64-bit versions of Windows.

Most of the types in this chapter come from the following namespaces:

System.Reflection
System.Resources
System.Globalization

What’s in an Assembly

An assembly contains four kinds of things:

An assembly manifest

Provides information to the CLR, such as the assembly’s name, version, and other assemblies that it references

An application manifest

Provides information to the operating system, such as how the assembly should be deployed and whether administrative elevation is required

Compiled types

The compiled IL code and metadata of the types defined within the assembly

Resources

Other data embedded within the assembly, such as images and ...