Working with Interfaces

• If a class contain all abstract functions then it is known as an Interface
• To create an Interface use interface keyword
• An interface can contain

          1)Abstract function
          2)Properties
          3)Indexes
          4)Events

• An Interface cannot contain

         1.Non-Abstract Functions
         2.Data Fields
         3.Constructors
         4.Destructors

• By default Interface functions are treated as Public and abstract
• An Interface can’t be instantiated directly
• Creating / deriving a new class or other Interface is compulsory / mandatory in order to provide implementation to its abstract function
• An interface can itself inherit from multiple interfaces
• An Interface is used to Implementation Multiple Inheritance in C#.NET
• In general an Interface provides control over the classes
• An Interface represents a contract, in that a class that implements an interface must implement every aspect of that interface exactly as it is defined
• Interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes
• We can define features as small groups of closely related members and can develop enhanced implementations for your interfaces without jeopardizing existing code, thus minimizing compatibility problems
• It is also possible to add new features at any time by developing additional interfaces and implementations
• Although interface implementations can evolve, interfaces themselves cannot be changed once published
• Changes to a published interface may break existing code
• If you think of an interface as a contract, it is clear that both sides of the contract have a role to play
• The publisher of an interface agrees never to change that interface, and the implementer agrees to implement the interface exactly as it was designed

      Example:-

      Class Diagram

 

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace CAInterface {     interface ClsEmployee     {         void GetEmpData();         void DisplayEmpData();     }     class ClsManager:ClsEmployee     {         int EmpId;         string EName;         double Bonus;         double Ca;         public void GetEmpData()         {             Console.WriteLine("Enter the Manager Id,Name,Bonus,Ca");             EmpId = Convert.ToInt32(Console.ReadLine());             EName = Console.ReadLine();             Bonus = Convert.ToDouble(Console.ReadLine());             Ca = Convert.ToDouble(Console.ReadLine());         }         public void DisplayEmpData()         {             Console.WriteLine("Manager  Details Are:-");             Console.WriteLine("Manager Id is:-     "+EmpId);             Console.WriteLine("Manager Name is:-   "+EName);             Console.WriteLine("Manager Bonus is:-  "+Bonus);             Console.WriteLine("Manager Ca is:-     "+Ca);                 }     }     class ClsInterface     {         static void Main(string[] args)         {             ClsManager obj1 = new ClsManager();             obj1.GetEmpData();             obj1.DisplayEmpData();             Console.ReadLine();         }     } }

Output :-