The .NET Solution

So much for the brief history lesson. The bottom line is that life as a Windows programmer has historically been tough. The .NET Framework is a rather radical and brute-force approach to making our lives easier. As you will see during the remainder of this book, the .NET Framework is a software platform for building systems on the Windows family of operating systems, as well as on numerous non- Microsoft operating systems such as Mac OS X and various Unix/Linux distributions. To set the stage, here is a quick rundown of some core features provided courtesy of .NET.

• Interoperability with existing code: This is (of course) a good thing. Existing COM binaries can commingle (i.e., interop) with newer .NET binaries and vice versa. As of .NET 4.0, interoperability has been further simplified with the addition of the dynamic keyword (covered in Chapter 18).
• Support for numerous programming languages: .NET applications can be created using any number of programming languages (C#, Visual Basic, F#, S#, and so on).
• A common runtime engine shared by all .NET-aware languages: One aspect of this engine is a well-defined set of types that each .NET-aware language understands.
• Complete and total language integration: .NET supports cross-language inheritance, cross-language exception handling, and cross-language debugging of code.
• A comprehensive base class library: This library provides shelter from the complexities of raw API calls and offers a consistent object model used by all .NET-aware languages.
• No more COM plumbing: IClassFactory, IUnknown, IDispatch, IDL code, and the variant-compliant data types (e.g., BSTR, SAFEARRAY) have no place in a .NET binary.
• A simplified deployment model: Under .NET, there is no need to register a binary unit into the system registry. Furthermore, .NET allows multiple versions of the same *.dll to exist in harmony on a single machine.

As you can most likely gather from the previous bullet points, the .NET platform has nothing to do with COM (beyond the fact that both frameworks originated from Microsoft). In fact, the only way .NET and COM types can interact with each other is using the interoperability layer.