Chetu Interview Question in .Net

Property in c#

Properties are named members of classes, structures, and interfaces. Member variables or methods in a class or structures are called Fields. Properties are an extension of fields and are accessed using the same syntax. They use accessors through which the values of the private fields can be read, written or manipulated.
Properties do not name the storage locations. Instead, they have accessors that read, write, or compute their values.
For example, let us have a class named Student, with private fields for age, name, and code. We cannot directly access these fields from outside the class scope, but we can have properties for accessing these private fields.

Accessors

The accessor of a property contains the executable statements that helps in getting (reading or computing) or setting (writing) the property. The accessor declarations can contain a get accessor, a set accessor, or both. For example:

// Declare a Code property of type string:
public string Code
{
   get
   {
      return code;
   }
   set
   {
      code = value;
   }
}

// Declare a Name property of type string:
public string Name
{
   get
   {
      return name;
   }
   set
   {
      name = value;
   }
}

// Declare a Age property of type int:
public int Age
{ 
   get
   {
      return age;
   }
   set
   {
      age = value;
   }
}

Example

The following example demonstrates use of properties:

using System;
namespace tutorialspoint
{
   class Student
   {
      private string code = "N.A";
      private string name = "not known";
      private int age = 0;
      
      // Declare a Code property of type string:
      public string Code
      {
         get
         {
            return code;
         }
         set
         {
            code = value;
         }
      }
      
      // Declare a Name property of type string:
      public string Name
      {
         get
         {
            return name;
         }
         set
         {
            name = value;
         }
      }
      
      // Declare a Age property of type int:
      public int Age
      {
         get
         {
            return age;
         }
         set
         {
            age = value;
         }
      }
      public override string ToString()
      {
         return "Code = " + Code +", Name = " + Name + ", Age = " + Age;
      }
   }
   
   class ExampleDemo
   {
      public static void Main()
      {
      
         // Create a new Student object:
         Student s = new Student();
         
         // Setting code, name and the age of the student
         s.Code = "001";
         s.Name = "Zara";
         s.Age = 9;
         Console.WriteLine("Student Info: {0}", s);
         
         //let us increase age
         s.Age += 1;
         Console.WriteLine("Student Info: {0}", s);
         Console.ReadKey();
      }
   }
}

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

Student Info: Code = 001, Name = Zara, Age = 9
Student Info: Code = 001, Name = Zara, Age = 10

Abstract Properties

An abstract class may have an abstract property, which should be implemented in the derived class. The following program illustrates this:

using System;
namespace tutorialspoint
{
   public abstract class Person
   {
      public abstract string Name
      {
         get;
         set;
      }
      public abstract int Age
      {
         get;
         set;
      }
   }
   
   class Student : Person
   {
   
      private string code = "N.A";
      private string name = "N.A";
      private int age = 0;
      
      // Declare a Code property of type string:
      public string Code
      {
         get
         {
            return code;
         }
         set
         {
            code = value;
         }
      }
      
      // Declare a Name property of type string:
      public override string Name
      {
         get
         {
            return name;
         }
         set
         {
            name = value;
         }
      }
      
      // Declare a Age property of type int:
      public override int Age
      {
         get
         {
            return age;
         }
         set
         {
            age = value;
         }
      }
      public override string ToString()
      {
         return "Code = " + Code +", Name = " + Name + ", Age = " + Age;
      }
   }
   
   class ExampleDemo
   {
      public static void Main()
      {
         // Create a new Student object:
         Student s = new Student();
         
         // Setting code, name and the age of the student
         s.Code = "001";
         s.Name = "Zara";
         s.Age = 9;
         Console.WriteLine("Student Info:- {0}", s);
         
         //let us increase age
         s.Age += 1;
         Console.WriteLine("Student Info:- {0}", s);
         Console.ReadKey();
      }
   }
}

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

Student Info: Code = 001, Name = Zara, Age = 9
Student Info: Code = 001, Name = Zara, Age = 10 

Property. On a class, a property gets and sets values. A simplified syntax form, properties are implemented in the IL as methods.
With properties,
 we create standard access points from external places. We access Name, 
not GetName(). This leads to simpler code. It provides data-binding 
features.
Get, set. We introduce an Example class. One field, an integer, is present. It is used as a backing store for the Number property.

Number:This is an int property. Number provides get { } and set { } implementations.

Get:The get { } implementation must include a return statement. It can access any member on the class.

Set:The set { } implementation receives the implicit argument "value." This is the value to which the property is assigned.

Value
 Based on: .NET 4.6 C# program that uses public int property
 using System;
class Example
{
 int _number;
public int Number
{
 get { return this._number; }
 set { this._number = value; }
}
}
class Program
{
static void Main()
{
Example example = new Example();
example.Number = 5;
// set { }
 Console.WriteLine(example.Number);
 // get { } }
} Output 5