Namespaces in C#

What are Namespaces in C#?

A namespace in C# is a logical container for organizing classes, interfaces, structs, and other types. It helps prevent naming conflicts by grouping related functionalities under a specific name.

Key Features of Namespaces

• Organizes code into logical groups.
• Avoids name conflicts in large projects.
• Allows aliasing for long or conflicting namespaces.
• Supports hierarchical structures for better code organization.

Declaring and Using Namespaces

Namespaces are declared using the namespace keyword, and they can be used with the using directive.

Example: Declaring and Using Namespaces

namespace MyNamespace
{
    public class Greeting
    {
        public void SayHello()
        {
            Console.WriteLine("Hello from MyNamespace!");
        }
    }
}

// Usage in another file
using MyNamespace;

class Program
{
    static void Main()
    {
        Greeting greet = new Greeting();
        greet.SayHello();
    }
}

// Output:
// Hello from MyNamespace!
        

Here, MyNamespace contains a class Greeting, which is accessed using the using directive.

Nested Namespaces

C# supports nested namespaces, allowing hierarchical organization of code.

Example: Nested Namespaces

namespace OuterNamespace
{
    namespace InnerNamespace
    {
        public class Sample
        {
            public void Display()
            {
                Console.WriteLine("Inside InnerNamespace");
            }
        }
    }
}

// Usage
using OuterNamespace.InnerNamespace;

class Program
{
    static void Main()
    {
        Sample obj = new Sample();
        obj.Display();
    }
}

// Output:
// Inside InnerNamespace
        

The InnerNamespace is inside OuterNamespace, making it easier to organize complex projects.

Using Namespace Aliases

Aliases help in resolving naming conflicts or shortening long namespace names.

Example: Namespace Alias

using Sys = System;  // Alias for System namespace

class Program
{
    static void Main()
    {
        Sys.Console.WriteLine("Using alias for System namespace!");
    }
}

// Output:
// Using alias for System namespace!
        

The alias Sys is used to refer to the System namespace, making code shorter and readable.

Commonly Used Built-in Namespaces

Best Practices for Using Namespaces

• Use meaningful namespace names that reflect functionality.
• Follow hierarchical structures to organize large projects.
• Use using statements at the top of files to avoid fully qualified names.
• Use aliasing when working with conflicting namespaces.
• Keep global namespaces clean and structured.