In this article I cover the area Interoperability issues. There is no doubt that with the help of .Net one can create powerful components and Distributed applications than any other language. But we have to think over about the past reusable components, which were created by many languages such as VB etc.

Is it the Usage of those past components is end after evolving of .Net? No we can use those components in the .Net and the .Net types in the Classic COM clients. Are there any possibilities of communication between managed and unmanaged types? Yes it is possible to make it possible to use existing COM objects (Unmanaged) from within managed applications and expose-managed objects to existing COM (Unmanaged) applications. Now let us see those things in detail.

In the first part of this article Part1, I focus on how .Net types calling c DLLs (Win32 API). In the Part2, I illustrate how you can Build a .NET Server Callable from COM clients and then in the later Part-3, I will explain you that how you can Build a .NET Client That Uses a COM Server.

Hopefully by the end of the article, you'd have achieved enough information to understand how Classic COM and the .NET framework can peacefully co-exist together. Hence if you're geared up, let's take an expedition through travel around how Classic COM can be used in the .NET world.