Namespaces and Assemblies in C#

In the C# and .NET world, the concepts of namespace and assembly are used to make code organized, manageable, and reusable. These structures allow code to be modularized, prevent naming conflicts, and make components easy to share, even in large projects.

Namespace

A namespace groups classes, interfaces, enums, and other types under a logical unit. This way, classes with the same name can be used without conflict under different namespaces.

namespace ProjectA.Models
{
    class User
    {
        public string Name { get; set; }
    }
}

namespace ProjectB.Models
{
    class User
    {
        public string FullName { get; set; }
    }
}

In this example, there are two different User classes. When namespaces are used, they can be accessed as ProjectA.Models.User or ProjectB.Models.User.

using Statement

The using statement provides direct access to the types inside a specific namespace.

using ProjectA.Models;

class Program
{
    static void Main()
    {
        User u = new User();
        u.Name = "John";
        Console.WriteLine(u.Name);
    }
}

Here, instead of writing ProjectA.Models.User, you can simply write User.

Assembly

An assembly is the deployable unit of compiled .NET code. It usually comes with the extension .dll (Dynamic Link Library) or .exe (executable).

• DLL: Cannot run on its own, referenced by other projects.
• EXE: Executable applications, usually containing an entry point (Main).

Assembly Contents

An assembly contains not only code but also metadata (e.g., version information) and resource files.

• Manifest: Defines the identity of the assembly (name, version, culture).
• MSIL Code: Compiled intermediate language code.
• Metadata: Information about classes, methods, and properties.
• Resources: Additional files such as images, icons, XML, etc.

TL;DR