C# 2010 All-in-One For Dummies®

Chapter 3. Helping Out with Interop

In This Chapter

• Using Dynamic Import

• Deploying without primary Interop assemblies

• Skipping the ref statement

The Component Object Model, usually called COM, is a standard for the interface of software bits at the binary level. Because it is binary, it is language-neutral, which was Microsoft's goal when the company introduced COM in 1993. COM is a language-neutral way to implement objects in a lot of different environments.

COM is as an umbrella term for a lot of different technologies in the Microsoft world. OLE, OLE2, ActiveX, COM+, and DCOM are all versions of the same idea — just implemented in different ways.

The problem with COM is networking. Although a thorough explanation is outside the scope of this book, it is important to understand that Microsoft's answer to broadly distributed applications in the 1990s was less than good. DCOM, or Distributed COM, was fraught with problems.

When XML Web services entered the scene in the late 1990s with SOAP, Microsoft just put a wrapper around COM that translated to and from SOAP. In the background, however, they were planning a much more sophisticated messaging system for Windows. That system eventually became ASP.NET Web services, and then WCF in its latest iteration.

Applications that are sewn to the desktop don't really use DCOM, though, so they have been slow to move to services, and therefore slow to move to .NET. These applications still live in COM, so we still need to interact with COM — even in ...