Access Specifiers in C#

Jan 3 2015 10:38PM

Mohammad Shaik

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Here Mohammad Shaik provided a short tutorial with example, about Access Specifiers in C#.

What is Access Specifiers ?

Access Modifiers (Access Specifiers) describes as the scope of accessibility of an Object and its members.
All C# types and type members have an accessibility level.
We can control the scope of the member object of a class using access specifiers.
We are using access modifiers for providing security of our applications.
When we specify the accessibility of a type or member we have to declare it by using any of the access modifiers provided by CSharp language.

Types of Access Specifiers:

public
private
protected
internal
protected internal

In tabular Form:

Modifier	Description
public	There are no restrictions on accessing public members.
private	Access is limited to within the class definition. This is the default access modifier type if none is formally specified
protected	Access is limited to within the class definition and any class that inherits from the class
internal	Access is limited exclusively to classes defined within the current project assembly
protected internal	Access is limited to the current assembly and types derived from the containing class. All members in current project and all members in derived class can access the variables.

public

public is the most common access specifier in C#.
It can be access from anywhere, that means there is no restriction on accessibility.
The scope of the accessibility is inside class as well as outside.
The type or member can be accessed by any other code in the same assembly or another assembly that references it.

There are no restrictions on accessing public members.

Accessibility:

Can be accessed by objects of the class
Can be accessed by derived classes

Example:

namespace MyApp1
{
    class access
    {
        // String Variable declared as public
        public string name;
        // Print method declared as public
        public void print()
        {
            Console.WriteLine("\nHi, My name is " + name);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            access objaccess = new access();
            Console.Write("Enter your name:\t");
            // Accepting value in public variable that is outside the class
            objaccess.name = Console.ReadLine();
            objaccess.print();

            Console.ReadLine();
        }
    }
}

When the above code is compiled and executed, it produces the following result:

Enter your name: Rejin
Hi, My name is Rejin

private

The scope of the accessibility is limited only inside the classes or struct in which they are declared.
The private members cannot be accessed outside the class and it is the least permissive access level.

Accessibility:

Cannot be accessed by object
Cannot be accessed by derived classes

Example:

namespace MyApp1
{
    class access
    {
        // String Variable declared as private
        private string name;
        // Method declared as Public
        public void print()
        {
            Console.WriteLine("\nMy name is " + name);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            access objaccess = new access();
            Console.Write("Enter your name:\t");
            // raise error because of its protection level
            objaccess.name = Console.ReadLine();
            objaccess.print();
            Console.ReadLine();
        }
    }
}

When the above code is compiled and executed, it produces the following result:

Output:
Error 1: Private_Access_Specifiers.access.name' is inaccessible due to its protection level

protected

The scope of accessibility is limited within the class or struct and the class derived (Inherited )from this class.
The protected access specifier hides its member variables and functions from other classes and objects.
This type of variable or function can only be accessed in child class.
It becomes very important while implementing inheritance.

Accessibility:

Cannot be accessed by object
By derived classes

Example:

namespace MyApp1
{
    class access
    {
        // String Variable declared as protected
        protected string name;
        public void print()
        {
            Console.WriteLine("\nMy name is " + name);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            access objaccess = new access();
            Console.Write("Enter your name:\t");
            // raise error because of its protection level
            objaccess.name = Console.ReadLine();
            objaccess.print();
            Console.ReadLine();
        }
    }
}

When the above code is compiled and executed, it produces the following result:

Output:
'Protected_Specifier.access.name' is inaccessible due to its protection level.

This is because; the protected member can only be accessed within its child class. You can use protected access specifiers as follow:

Example:

using System;

namespace Protected_Specifier
{
  class access
   {
     // String Variable declared as protected
     protected string name;
     public void print()
      {
        Console.WriteLine("\nMy name is " + name);
      }
   }

  class Program : access // Inherit access class
   {
     static void Main(string[] args)
      {
        Program p=new Program();
        Console.Write("Enter your name:\t");
        p.name = Console.ReadLine(); // No Error!!
        p.print();
        Console.ReadLine();
      }
   }
}

When the above code is compiled and executed, it produces the following result:

Output:
Enter your name: Rejin
My name is Rejin

Internal

The internal access modifiers can access within the program that contain its declarations and also access within the same assembly level but not from another assembly.
The internal access specifier hides its member variables and methods from other classes and objects, that is resides in other namespace.
The variable or classes that are declared with internal can be access by any member within application. It is the default access specifiers for a class in C# programming.

Accessibility:

In same assembly (public)

Can be accessed by objects of the class
Can be accessed by derived classes

In other assembly (internal)

Cannot be accessed by object
Cannot be accessed by derived classes

Example:

namespace Internal_Access_Specifier
    {
        class access
        {
            // String Variable declared as internal
            internal string name;
            public void print()
            {
                Console.WriteLine("\nMy name is " + name);
            }
        }

        class Program
        {
            static void Main(string[] args)
            {
                access objaccess = new access();
                Console.Write("Enter your name:\t");
                // Accepting value in internal variable
                objaccess.name = Console.ReadLine();
                objaccess.print();
                Console.ReadLine();
            }
        }
    }

When the above code is compiled and executed, it produces the following result:

Output:
Enter your name: Rejin
My name is Rejin

protected internal

Protected internal is the same access levels of both protected and internal.
It can access anywhere in the same assembly and in the same class also the classes inherited from the same class.
The protected internal access specifier allows its members to be accessed in derived class, containing class or classes within same application.
However, this access specifier rarely used in C# programming but it becomes important while implementing inheritance.

Example:

namespace Internal_Access_Specifier
    {
        class access
        {
            // String Variable declared as protected internal
            protected internal string name;
            public void print()
            {
                Console.WriteLine("\nMy name is " + name);
            }
        }

        class Program
        {
            static void Main(string[] args)
            {
                access objaccess = new access();
                Console.Write("Enter your name:\t");
                // Accepting value in protected internal variable
                objaccess.name = Console.ReadLine();
                objaccess.print();
                Console.ReadLine();
            }
        }
    }

When the above code is compiled and executed, it produces the following result:

Output:
Enter your name: Rejin
My name is Rejin

I hope this page will helps to learn Access Specifiers in C#. Thanks.

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