Programming languages are evolving very fast, but their principles are almost the same. There are two main concepts about the writing process of software, Closed Code and Open-Source Software. Most developers prefer to have the source code of the software developed by other developers so they can understand, read, and change the product very easily. Even when a product is an open source, the number of developers who modify the product is very low compared to the number of users who use the product. In this paper we will present an implementation of reflective programming in .NET to allow other developers to extend the capabilities of a product with their contributions on writing source code even if the project is not open source.