- Debugging Client-Side JavaScript for ASP.NET with Visual Studio
- Using Entity SQL As Your Data Access Layer
- Programming with LINQ to XML for Objects
- Bill Wagner on C#, LINQ, and Writing Books
- Writing LINQ Queries with the Entity Framework
- Using Parallel LINQ
- Programming with Anonymous Types in C#
- Querying SQL with LINQ
- Writing Lambda Expressions in the .NET Framework
- Programming with Generic Delegates in .NET
- Managing Database Transactions with the TransactionScope
- Letting ADO.NET Write Your SQL
- Using C#'s yield to Return an Enumerable Collection
- Using the My Feature in Visual Basic .NET
- Programming with the BackgroundWorker Component in .NET 2.0
- How to Use Partial Classes in Visual Studio 2005
- Generic Classes in C# 2.0
- Anonymous Methods in C# 2.0
- Implementing an XML Section Handler in .NET
- .NET Remoting: Handling Remote Server Events
- Converting XML Nodes into Objects
- Using Application Blocks for Data Access
- A Roll of the Dice: Building a Small Game Using Windows Graphics Programming
- Through the Looking Glass: Debugging Hosted .NET Applications
- Listening to Trace Messages in NUnit
- Instrumenting Your Code for Exception Management
- What's .NET Remoting, And Why Should You Care?
- Injecting Dynamic JavaScript to Focus ASP.NET Controls
- Defining Add and Remove Accessor Methods for Events in VB.NET
- Debugging .NET with NUnit
- Dynamic Debug Code Management with BooleanSwitches
- Creating Typed DataSets with XML Schemas
- Fall Comdex 2002: .NET or .What?
- Managing Session State for ASP.NET
- Creating Project Templates in .NET
- Creating Custom Attributes in Visual Basic .NET
- Asynchronous Web Services
- Inheritance and Polymorphism in VB.NET
- Serializing Objects to a .NET DataSet
- Implementing the Strongly Typed Collection in C#
- Emitting MSIL with Reflection
- Programming with Regular Expressions in C#
- Creating Data-Enabled Web Pages using the DataList
- Creating Visual Studio .NET Add-Ins
- Lightweight Threading with Thread Pools in Visual Basic .NET
- Understanding Delegates in Visual Basic .NET
- Working with New Abstract Data Types in Visual Basic .NET
- Storing Your Access Data
- Adding Data to Web Pages
Sorry, this author hasn't posted any blogs.
This chapter is from the book
Visual Basic .NET Unleashed
In This Chapter
- Inheritance Basics
- What Is Inheritance?
- Defining Classes That Must Be Subclassed
- Defining Classes That Cannot Be Subclassed
- Polymorphism
- Dynamic Typecasting
- Defining Interfaces
- Summary
Visual Basic .NET supports inheritance. VB6 did not. VB6 supported interface implementation, which is a facility of the Component Object Model (COM). Why Microsoft chose to implement COM and interfaces before classes and inheritance is anybody's guess, but Visual Basic .NET supports both interfaces and inheritance. The net result is that Visual Basic .NET is significantly more powerful and has features and capabilities consistent with the most advanced languages available today.
Through version 6, we said that Visual Basic was object-based rather than object- oriented. The primary missing ingredient was inheritance. Visual Basic .NET rectifies this deficit.
Chapter 10 demonstrates how to use inheritance in Visual Basic .NET, as well as the new capabilities associated with inheritance relationships. Additionally there are revisions to the way interfaces are supported in Visual Basic .NET. Chapter 10 will demonstrate inheritance, virtual abstract classes, final classes, polymorphic behavior, dynamic typecasting, and how to define and implement interfaces in Visual Basic .NET.
Inheritance Basics
Interfaces contain declarations only. Classes can contain both declarations and definitions. Classes can implement interfaces as well as inherit from a single parent class. Interfaces use the keyword Interface, and classes use the keyword Class in Visual Basic .NET.
The difference between an interface and a class is that classes provide implementations for their members and interfaces define members without implementations. Both classes and interfaces support inheritance. A class may inherit from a single parent and implement zero or more interfaces, and interfaces support multiple interface inheritance but provide no implementation. (We will return to interfaces later in this chapter. For now let's focus on what classes offer.) Even if your understanding of inheritance is expert, you are encouraged to read the remainder of this section simply to see the grammar used to support class inheritance in Visual Basic .NET.
Account Sign In
View your cart