What exactly is an Assembly in C# or .NET?
Could you please explain what is an Assembly in C# or .NET?
- Where does it begin and where does it end?
- What important information should I know about Assemblies?
Answer
An assembly is the compiled output of your code, typically a DLL, but your EXE is also an assembly. It's the smallest unit of deployment for any .NET project.
The assembly typically contains .NET code in MSIL (Microsoft Intermediate language) that will be compiled to native code ("JITted" - compiled by the Just-In-Time compiler) the first time it is executed on a given machine. That compiled code will also be stored in the assembly and reused on subsequent calls.
The assembly can also contain resources like icons, bitmaps, string tables and so on. Furthermore, the assembly also contains metadata in the assembly manifest - information like version number, strong name, culture, referenced assemblies and so forth.
In 99% of your cases, one assembly equals a physical file on disk - the case of a multi-file assembly (one assembly, distributed across more than a single file) appears to be a rather odd-ball edge case which I've never encountered so far in my 5+ years of .NET development.
In a multifile assembly there would still be only one assembly manifest in a DLL or EXE and the MSIL code in multiple netmodule files.