Appendix A. Writing Code for Cross-Language Interoperability
IN THIS APPENDIX
With .NET, you have the ability to create components in one language that can then be consumed by applications written in another language. This is nothing particularly new, because COM enabled you to write COM components in VB and call them from C++ applications, and vice versa. However, .NET gives you the ability to perform such actions as inheriting a VB .NET component in a C# application, or having your VB .NET application inherit a COBOL .NET component that is inheriting from a J#.NET component.
This level of interoperability is far beyond what COM gave you, but it doesn't come without its own set of rules. The rules can be broken within individual languages, but breaking the rules prevents you from being assured that the code you write can interoperate properly with other .NET languages.