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- C# - File I/O
- C# - Exception Handling
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- C# - Namespaces
- C# - Interfaces
- C# - Operator Overloading
- C# - Polymorphism
- C# - Inheritance
- C# - Classes
- C# - Enums
- C# - Structure
- C# - Strings
- C# - Arrays
- C# - Nullables
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- C# - Decision Making
- C# - Operators
- C# - Constants
- C# - Variables
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C# Advanced Tutorial
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- C# - Delegates
- C# - Indexers
- C# - Properties
- C# - Reflection
- C# - Attributes
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C# - Namespaces
C# - Namespaces
A namespace is designed for providing a way to keep one set of names separate from another. The class names declared in one namespace does not confpct with the same class names declared in another.
Defining a Namespace
A namespace definition begins with the keyword namespace followed by the namespace name as follows −
namespace namespace_name {
// code declarations
}
To call the namespace-enabled version of either function or variable, prepend the namespace name as follows −
namespace_name.item_name;
The following program demonstrates use of namespaces −
using System;
namespace first_space {
class namespace_cl {
pubpc void func() {
Console.WriteLine("Inside first_space");
}
}
}
namespace second_space {
class namespace_cl {
pubpc void func() {
Console.WriteLine("Inside second_space");
}
}
}
class TestClass {
static void Main(string[] args) {
first_space.namespace_cl fc = new first_space.namespace_cl();
second_space.namespace_cl sc = new second_space.namespace_cl();
fc.func();
sc.func();
Console.ReadKey();
}
}
When the above code is compiled and executed, it produces the following result −
Inside first_space Inside second_space
The using Keyword
The using keyword states that the program is using the names in the given namespace. For example, we are using the System namespace in our programs. The class Console is defined there. We just write −
Console.WriteLine ("Hello there");
We could have written the fully quapfied name as −
System.Console.WriteLine("Hello there");
You can also avoid prepending of namespaces with the using namespace directive. This directive tells the compiler that the subsequent code is making use of names in the specified namespace. The namespace is thus impped for the following code −
Let us rewrite our preceding example, with using directive −
using System;
using first_space;
using second_space;
namespace first_space {
class abc {
pubpc void func() {
Console.WriteLine("Inside first_space");
}
}
}
namespace second_space {
class efg {
pubpc void func() {
Console.WriteLine("Inside second_space");
}
}
}
class TestClass {
static void Main(string[] args) {
abc fc = new abc();
efg sc = new efg();
fc.func();
sc.func();
Console.ReadKey();
}
}
When the above code is compiled and executed, it produces the following result −
Inside first_space Inside second_space
Nested Namespaces
You can define one namespace inside another namespace as follows −
namespace namespace_name1 {
// code declarations
namespace namespace_name2 {
// code declarations
}
}
You can access members of nested namespace by using the dot (.) operator as follows −
using System;
using first_space;
using first_space.second_space;
namespace first_space {
class abc {
pubpc void func() {
Console.WriteLine("Inside first_space");
}
}
namespace second_space {
class efg {
pubpc void func() {
Console.WriteLine("Inside second_space");
}
}
}
}
class TestClass {
static void Main(string[] args) {
abc fc = new abc();
efg sc = new efg();
fc.func();
sc.func();
Console.ReadKey();
}
}
When the above code is compiled and executed, it produces the following result −
Inside first_space Inside second_spaceAdvertisements