Class Libraries and Reusability in C#

 19th Day

Hey Guys, I hope that you are Enjoying with my blogs in previous block we studied basic of C#, Its Installation, IL code by just in  time make it machine code and Today's we will study about Basic concepts of C#, Class  Libraries and Reusability.

• .NET is a free, cross-platform, open source developer platform for building many different types of applications.
• .NET Core is a cross-platform .NET implementation for websites, servers, and console apps on Windows, Linux, and macOS.
• With .NET, you can use multiple languages, editors, and libraries to build for web, mobile, desktop, games, and IoT.

• So lets create one console app(.NET core)  project for better understanding to this concept.
• It is an exe i.e executable. we can double click and execute this folder. 
• Build now and right click on console app open as an explorer go to bin folder and will get exe folder. 
• Input:(Program.cs)

using System;

using ClassLibrary1;

namespace ConsoleApp2

{

    class Program

    {

        static void Main(string[] args)

        {

           

            Class1 x = new Class1();// we can call here to class1

            Console.WriteLine(x.Add(10,20));

            // here we giving parameter to add function

            Console.WriteLine("Hello World!");

            Console.Read();

        }

    }

}

• To make DLL, Will have to create a Class library.
• DLL stands for dynamic link library it is library that contains function and codes that can used by more than one program at a time. Once we have created DLL we can use in many application. 
• Input:(Class1.cs)
  using System;

  
  

  namespace ClassLibrary1

  {

      public class Class1

      {

          public int Add(int num1, int num2)

          {

              return num1 + num2; 

          }

      }

  }

• This code we can execute but can't link it.
• After build it, If we want to see DLL file go to its bin folder then executable file not will show , it show dll(dynamic link library) like given below

• We can't run this folder by double click because its not an executable it is Dynamic link library.so we can call to its function from another class.
• For reference to console app ,go to right side-> right click on dependency -> add project reference-> class library.
• Assembly has two types of library 1. Exe  2. DLL.
• Output:
  
  
  

                             Must refer this videos for more details:

                                         Thank You...!