The Role of COM

When the .NET Framework was introduced in 2002, some uninformed journalists interpreted it as the death of COM. That turned out to be completely incorrect. COM is not going anywhere for a while. In fact, Windows will not boot without COM.

.NET integrates very well with COM-based software. Any COM component can be treated as a .NET component by native .NET components. The .NET Framework wraps COM components and exposes an interface that .NET components can work with. That makes.NET interoperable with a tremendous amount of older COM-based software.

Going in the other direction, the .NET Framework can expose .NET components with a COM interface. This enables older COM components to use .NET-based components as if they were developed using COM.

Chapter 23 discusses COM interoperability in more detail.

No Internal Use of COM

Understand, however, that native .NET components do not interface using COM. The CLR implements a new way for components to interface, one that is not COM-based. Use of COM is only necessary when interfacing with COM components produced by non-.NET tools.

Over a long span of time, the fact that .NET does not use COM internally may lead to the decline of COM, but for any immediate purposes, COM is definitely important.