Summary

In this chapter, you have seen how the different generations of COM and .NET applications can interact. Instead of rewriting applications and components, a COM component can be used from a .NET application just like a .NET class. The tool that makes this possible is tlbimp, which creates a runtime callable wrapper (RCW) that hides the COM object behind a .NET façade.

Likewise, tlbexp creates a type library from a .NET component that is used by the COM callable wrapper (CCW). The CCW hides the .NET component behind a COM façade. Using .NET classes as COM components makes it necessary to use some attributes from the namespace System.Runtime .InteropServices to define specific COM characteristics that are needed by the COM client.