Circular reference among two .net assemblies

Question

I have two assemblies A & B.

A has existing reference to B and it must be kept that way. Right now I made some changes to B that need to refer to A. So circular

Answer 1

This is a problem with the language design of C#. In C/C++ you would just use a header to define the interface of the compilation unit and the dependency is resolved.

In C# there are no headers. You have three options

1. 1> merge the assemblies (increase in compilation time and may not
   make sense if the assemblies are functionally unrelated). C# often forces you to do this, even if the assemblies should logically be separate.
2. Dependency injection
3. Creating a third assembly with interfaces which both the modules reference. This accomplishes the dependency injection through a C# language mechanism (interfaces), instead of roll your own; but its the same thing.

Number 3 is typically how these situations are handled in C# but its not as elegant as C/C++ solution to this problem. For large code bases you have to design from the start with this in mind.