Creating a Class Library

Class library projects don’t need to contain the Main method, because a library isn’t an executable. It can’t run but can be used inside other projects.

Let’s create and use a class library in Visual Studio.

First, create a console application that serves as an executable. After creation, we have a window similar to the following:

Right-click the “Solution” node in the “Solution Explorer” and click “Add” -> “New Project.”

Set “Class library” as the project type and finish the project creation.

Our solution now contains two projects.

Let’s create an Employee class with the following contents:

using System;

namespace EmployeeDirectory
{
    public class Employee
    {
        public string firstName;
        public string lastName;

        public Employee(string firstName, string lastName)
        {
            this.firstName = firstName;
            this.lastName = lastName;
        }

        public void PrintFullName()
        {
            Console.WriteLine($"{firstName} {lastName}");
        }
    }
}

Now, in order to use our new class library, we must reference it from the place where we want to use it.

Right-click the “Dependencies” node inside the console project and click “Add Project Reference.”

From the list, check the class library project and click “OK”:

With the using directive, we now can import the namespaces that reside in the class library project and start using the classes from there.

using EmployeeDirectory;

namespace MyFirstProgram
{
    class Program
    {
        static void Main(string[] args)
        {
            Employee employee = new Employee("John", "Doe");
            employee.PrintFullName();
        }
    }
}