What is the difference between namespace and assembly?

An assembly is a physical grouping of logical units while namespace groups classes. A namespace can span multiple assemblies.

In .NET, namespaces and assemblies serve different purposes, although they are related concepts. Here’s the difference between them:

  1. Namespace:
    • A namespace is a logical container for organizing code elements such as classes, structs, interfaces, enums, and delegates.
    • It helps in avoiding naming conflicts and provides a way to organize and group related code elements.
    • Namespaces allow you to create modular and organized code by providing a hierarchical naming system.
    • Namespaces can span multiple assemblies.
  2. Assembly:
    • An assembly is the primary building block of a .NET application, consisting of one or more files (DLLs or EXEs) that contain compiled code (IL – Intermediate Language), resources, and metadata.
    • It is the unit of deployment, versioning, and security in .NET.
    • Assemblies can be executed directly (EXE) or referenced by other assemblies (DLL).
    • An assembly may contain one or more namespaces.

In summary, a namespace is a way to logically organize code within an assembly or across multiple assemblies, whereas an assembly is a physical deployment unit that contains compiled code, metadata, and resources. Namespaces are used to avoid naming conflicts and to organize code, while assemblies are used for deployment, versioning, and security.