Introduction

Overview

With the release of .NET, Microsoft has introduced a whole raft of new technol ogies, and has even invented a new programming language. At the same time, Microsoft has updated many existing technologies and redefined the way in which Microsoft Windows applications are written.

If you read much about .NET, youd be forgiven for thinking everything youve used for years has been consigned to the trash canthe Windows API, COM, COM+, ActiveX controls...all gone. Nothing could be further from the truth.

The Windows API is still part of current Windows versions, and COM and COM+ are part of the Windows infrastructure. In addition to companies and developers having a huge investment in COM and COM+ code, these technol ogies are so tied to the way Windows works that they will be around for a long time to come. Microsoft recognizes this and has put a great deal of work into ensuring that COM, COM+, and .NET code can operate together. You can use your existing COM code in .NET projects, write .NET components that will work with COM clients , and even host .NET components in COM+. You dont have to throw away anything youve already produced if you dont want to.

You can also call Windows API functionsor other functions hosted in DLLsfrom .NET code, so you dont have to rewrite your existing APIs to use them with a .NET client.

The name of the game is interoperability, and this book will show you how to bridge the gap between unmanaged code and .NET. By the time youve finished reading, youll have an appreciation of how to transition seamlessly between .NET and the world of traditional Windows code, and youll be able to move into the new world of .NET while maintaining compatibility with your existing code base.