Microsoft 9GD00001 User Manual

 

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Microsoft Visual Studio 2010: A Beginner’s Guide

Now that you can define a new class, create an instance from that class, and use it, the 

next section shows you another feature of classes called inheritance.

Class Inheritance

One class can reuse the members of another through a feature known as inheritance. In 
programming terms, we say a child class can derive from a parent class and that child 
class will inherit members (such as fields and methods) of the parent class that the parent 
class allows to be inherited. The following example will create a Cashier class that 
derives from the Employee class. To create this class, right-click the project, select Add | 
Class, and name the class Cashier. Listing 3-3 shows the new class and modifications for 
implementing inheritance.

Listing 3-3 

  Class inheritance

C#:

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
 
namespace FirstProgram 
{ 
    public class Cashier : Employee 
    { 
    } 
}

VB:

Public Class Cashier 
    Inherits Employee 
 
End Class

The C# inheritance relationship is indicated by the colon after the Cashier identifier, 

followed by the class being derived from, Employee. In VB, you write the keyword 
Inherits,

 on a new line, followed by the class being derived from. Essentially, this means 

that Cashier has all of the same members as Employee. Listing 3-4 demonstrates the 
benefits of inheritance.