c# classes

Static Class and Methods

Static classes and class members are used to create data and functions that can be accessed without creating an instance of the class.

The main features of a static class are:

·         They only contain static members.

·         They cannot be instantiated.

·         They are sealed.

·         They cannot contain Instance Constructors(Instance constructors are used to create and initialize instances. The class constructor is invoked when you create a new object)

·         Static classes are sealed and therefore cannot be inherited

Static Constructor:
A static constructor is used to initialize any static data, or to perform a particular action once only.

·         A static constructor does not take access modifiers or have parameters.

·         A static constructor is called automatically to initialize the class before the first instance is created or any static members are referenced.

·         A static constructor cannot be called directly.

·         The user has no control on when the static constructor is executed in the program.

·         Static constructors are also useful when creating wrapper classes for unmanaged code.

class CompanyInfo

{

    public static  string GetCompanyName() { return "CompanyName"; }

    public static string GetCompanyAddress() { return "CompanyAddress"; }

  

}

namespace consoleTestApplication

{

    class Program

    {

        static void Main(string[] args)

        {

            string COMPANYADDRESS = CompanyInfo.GetCompanyAddress(); 

            

        }

    }

}

Explicit Interface

Two interfaces that contain a member with the same signature
Class that implements those interfaces should call those methods explicitly.

interface ICpmpany

{

     void Display();

}

interface IBranch

{

     void Display();

}

class DisplayName : ICpmpany, IBranch

{

    // Both ISurface.Paint and IControl.Paint call this method.

     void ICpmpany.Display()

    {

        System.Console.WriteLine("company");

     }

     void IBranch.Display()

     {

         System.Console.WriteLine("branch");

     }

}

namespace consoleTestApplication

{

    class Program

    {

        static void Main(string[] args)

        {

           DisplayName obj = new DisplayName();

            //obj.Display();                          // compile error

           ICpmpany cmpobj = (ICpmpany)obj;

           IBranch brcobj = (IBranch)obj;

           cmpobj.Display();

           brcobj.Display();

           System.Console.ReadLine();

        }

    }

}