Chapter 1. Visual Basic .NET andthe .NET Framework

Programming Visual Basic .NET is a comprehensive guide to the .NET version of the Visual Basic language and its use as a tool for programming on Microsoft’s .NET platform. One learns VB.NET specifically to create .NET applications; pretending otherwise would miss the point of the language. Thus, this book does not consider VB.NET in a vacuum but places the language firmly in the context of Microsoft’s .NET platform and in the development of desktop and Internet applications.

This chapter introduces both the Visual Basic .NET language and the .NET platform, including the .NET Framework.

Visual Basic and .NET

Once upon a time there was a programming language called Basic, which stood for Beginner’s All-purpose Symbolic Instruction Code. As the name suggests, Basic was intended to be as simple and accessible as possible for those unfamiliar with programming.

Then in 1991 Microsoft unveiled Visual Basic, a retooling of Basic that changed the way user interfaces were written. Visual Basic can still lay claim to being one of the most popular programming languages ever developed.

Visual Basic .NET is Microsoft’s reengineering of Visual Basic for the .NET platform. VB.NET departs in some significant ways from earlier versions of Visual Basic. In fact, some early adopters of VB.NET started calling it VB.NOT. VB.NET has evolved into a full-fledged object-oriented commercial software development package. Yet VB.NET also retains some of the inherent simplicity of its predecessors.

VB.NET has a number of features that help it maintain backwards compatibility with Visual Basic 6 (VB6). Other features have been added specifically to adapt Visual Basic to object-oriented programming and the .NET platform.

VB.NET provides support in the language to find bugs early in the development process. This makes for code that is easier to maintain and programs that are more reliable. VB.NET does not support some features available in other languages (e.g., pointers) that make for unsafe code.

In the past, you might have learned a language like C or Java without much concern about the platform on which you would be programming. These cross-platform language were as comfortable on a Unix box as they were on a PC running Windows.

VB.NET, however, is a version of the Visual Basic language written specifically for .NET. While .NET may become cross-platform some day soon—a Unix port is already available—for now, the overwhelming majority of .NET programs will be written to run on a machine running Windows.

Stepchild No Longer

VB.NET represents a significant step forward for Visual Basic programmers. In the past, VB has been (unfairly) cast as a second-class “toy” language that was not up to the challenge of enterprise-level software development.

Whatever the merits of that accusation for VB6 and its predecessors, it is manifestly untrue for VB.NET. The code produced by Visual Basic .NET is (nearly) identical to that produced by C# or any other compiler designed for .NET. There is no performance or size penalty to writing with Visual Basic .NET.

In fact, the differences between Visual Basic .NET and C# are entirely syntactic. That is, one language uses semicolons, the other does not. One language uses brackets, the other parentheses. The differences are so simple, and so straightforward, that converting a C# program to Visual Basic .NET is an entirely mechanical operation, one that can be performed by a simple program; such programs are already available on the Web.

The truth is that there is no Visual Basic .NET language, nor is there a C# language. There is, in fact, a single .NET language called MSIL (Microsoft Intermediate Language). Both Visual Basic .NET and C# compilers produce MSIL code, and the code they produce is nearly identical!

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