In the C#, namespaces are used to organize and provide multiple classes, structs, interfaces, enums and delegates. It use to control the scope of methods and classes in larger .Net programming.
In a simple C# program we use Console.WriteLine in console application where System is the namespace and Console is the class. To access the class of a namespace, you need to use namespace class name. You can use using keyword so that you don't have to use complete name all the time.
A namespace can have following types as its members:
- Namespaces (Nested Namespace)
- Classes
- Interfaces
- Structures
- Delegates
C# namespace using keyword example
using System; //this is using keyword
namespace NameSpaceExample//this is created namespace
{
public class Program
{
public static void Main(string[] args)
{
Console.WriteLine("Hello FindAndSolve");
}
}
}
Output
Hello FindAndSolve
C# Define a Multiple Namespaces
In c#, you can define and access multiple namespaces in your application with using keyword.
Example
using System;
namespace FirstNameSpace {
public class FirstHelloClass {
public void sayHello() { Console.WriteLine("Hello First Namespace"); }
}
}
namespace SecondNameSpace
{
public class SecondHelloClass
{ public void sayHello() { Console.WriteLine("Hello Second Namespace"); }
}
}
public class TestNamespace { public static void Main()
{
FirstNameSpace.FirstHelloClass objFirst = new FirstNameSpace.FirstHelloClass();
SecondNameSpace.SecondHelloClass objSecond = new SecondNameSpace.SecondHelloClass(); objFirst.sayHello();
objSecond.sayHello();
}
}
Output
Hello First Namespace
Hello Second Namespace
Nested Namespaces in C#
In the c#, a namespace under another namespace is called a Nested Namespace. The nested namespace classes and their class or member can be accessed by using the dot (.) operator like as given below.
Syntax
namespace MainNameSpace{
namespace NestedNameSpace{
// Nested Namespace Code
}
}
Example
using System;
using CustomNameSpace.Nested;
namespace FindAndSolve
{
public class Program
{
public static void Main(string[] args)
{
Welcome w = new Welcome();
w.GreetMessage();
}
}
}
namespace CustomNameSpace {
namespace Nested { public class Welcome
{
public void GreetMessage()
{
Console.WriteLine("Welcome to FinsAndSolve");
}
}
}
}
Output
Welcome to FinsAndSolve