How to implement inheritance using VB.NET/C#?

Question

Is there any VB.NET equivalent to the C# var keyword?

Answer 1

When we set out to implement a class using inheritance, we must first start with an existing class from which we will derive our new subclass. This existing class, or base class, may be part of the .NET system class library framework, it may be part of some other application or .NET assembly, or we may create it as part of our existing application. Once we have a base class, we can then implement one or more subclasses based on that base class. Each of our subclasses will automatically have all of the methods, properties, and events of that base class ? including the implementation behind each method, property, and event. Our subclass can add new methods, properties, and events of its own - extending the original interface with new functionality. Additionally, a subclass can replace the methods and properties of the base class with its own new implementation - effectively overriding the original behavior and replacing it with new behaviors. Essentially inheritance is a way of merging functionality from an existing class into our new subclass. Inheritance also defines rules for how these methods, properties, and events can be merged.

Answer 2

Inheritance: BaseClass.cs

using System;

public class ParentClass
{
    public ParentClass()
    {
        Console.WriteLine("Parent Constructor.");
    }

    public void print()
    {
        Console.WriteLine("I'm a Parent Class.");
    }
}

public class ChildClass : ParentClass
{
    public ChildClass()
    {
        Console.WriteLine("Child Constructor.");
    }

    public static void Main()
    {
        ChildClass child = new ChildClass();

        child.print();
    }
}

Output:

Parent Constructor.
Child Constructor.
I'm a Parent Class.

Derived Class Communicating with Base Class: BaseTalk.cs

using System;

public class Parent
{
    string parentString;
    public Parent()
    {
        Console.WriteLine("Parent Constructor.");
    }
    public Parent(string myString)
    {
        parentString = myString;
        Console.WriteLine(parentString);
    }
    public void print()
    {
        Console.WriteLine("I'm a Parent Class.");
    }
}

public class Child : Parent
{
    public Child() : base("From Derived")
    {
        Console.WriteLine("Child Constructor.");
    }
    public new void print()
    {
        base.print();
        Console.WriteLine("I'm a Child Class.");
    }
    public static void Main()
    {
        Child child = new Child();
        child.print();
        ((Parent)child).print();
    }
}

Output:

From Derived
Child Constructor.
I'm a Parent Class.
I'm a Child Class.
I'm a Parent Class.