Inheritance in C-Sharp

This is the mechanism in which one object reuses the functionality, properties, and methods of another object. This brings reusability to the table, so instead of creating another very similar object, create a base, and from that inherit all the children objects.

Take, for example, the following class in C-Sharp:

public class Employee(string Name, int Wage, string Department)
{
    public string Name { get; init; } = Name;
    protected int Wage { get; set; } = Wage;
    public string Department { get; set; } = Department;
 
    public void Greet() => Console.WriteLine($"Hi, I'm {Name} and I work at {Department}!");
}

One could derive a Developer child class from the Employee parent class, using : to refer to the parent class. Note that you should include the parent class inside the constructor using the base keyword. There’s no need to redefine the fields from the parent class. For overriding already existent methods or fields, check the note Polymorphism in C-Sharp.

public class Developer: Employee
{
    public string Stack;
    public int YearsExperience;
    public virtual int Wage;
 
    // Creating a constructor for readability.
    public Developer(string Name, string Department, string Stack, int YearsExperience, int Wage) : base(Name, Wage, Department)
            {
                this.Stack = Stack;
                this.YearsExperience = YearsExperience;
            }
 
    public virtual void Greet() =>
        Console.WriteLine(
            $"Hi, i'm {Name} and have been working with {Stack} at {Department} for {YearsExperience} years."
        );
}

Refactoring using primary constructors, it would end up like this:

public class Employee(string Name, int Wage, string Department)
{
    public string Name { get; init; } = Name;
    protected int Wage { get; set; } = Wage;
    public string Department { get; set; } = Department;
 
    public void Greet() => Console.WriteLine($"Hi, I'm {Name} and I work at {Department}!");
}
 
 
public class Developer(string Name, string Department, string Stack, int YearsExperience, int Wage) : Employee(Name, Wage, Department)
{
    public string Stack { get; set; } = Stack;
    public int YearsExperience { get; set; } = YearsExperience;
    public new int Wage { get; set; } = Wage;
 
    public new void Greet() =>
        Console.WriteLine(
            $"Hi, i'm {Name} and have been working with {Stack} at {Department} for {YearsExperience} years."
        );

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• The protected keyword

Using protected, like the code snippet above, it blocks access from outside the class, except for other classes inheriting from the parent.

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