.NET Assemblies - II

This is a three series article.

1. In the first part we discussed the 3-tier architecture.

2. In part-II of this article we will see what the .NET assemblies are and

3. In the last part we will be practically implementing a simple .NET assembly.

Part-II :: Introduction to .NET Assemblies

ASP .NET introduces many techniques for better code management and code reusability. Code Behind and Custom Controls are one of the best implementations of these techniques where you can separate your HTML tags and coding from your server-side script. It also provides future  facilities to manage the code easily.

The Code Behind and Custom Controls development is a good approach to better web development, but there is a performance hit that also exists. You may know about the CLR (Common Language Runtime), I will not go into the detail of this, but just for a brief introduction, it is the "black box" or the "heart" of the .NET where the compilation of your code takes place. Whenever an ASP .NET page  is opened or requested by the user, the page gets compiled first and then is transferred to the user. The compilation process is also completed in two steps. First of all an IL (Intermediate Language) is generated and then this is handed over for JIT (Just In Time) compilation  which produces the machine code and our pages get displayed with their dynamic content.

The performance of our web application can be improved by creating pre-compiled libraries of IL which can then be handed over to JIT directly without having the inclusion of an extra process to make the conversion. This method is called componentization. Components are pre-compiled set of classes that have been developed in the form of DLL files and can then be included within our projects. This is also known as an assembly.

"An assembly is a logical grouping of functionality in a physical file."

Understanding the assemblies and their concepts is the focus of this article. An assembly has many benefits some of which are.

1. Increased performance.

2. Better code management and encapsulation.

3. Introduces the n-tier concepts and business logic.

You might have heard of the n-tier and three-tier architecture concepts. (To know about the detail of 3-tier architectural concepts please read Part-I of this article.). The practical implementation of the three-tier architecture is also implemented by using the assemblies. In the first part of this article we discussed about the Business Logic layer. This layer is where we place all the business rules that apply to the transactions that take place between the client and the server, and this layer is implemented through components. The reason for this is that one we hide our code and the business rules that have been applied (since the components are in compiled binary form, so they are a mean of code encapsulation) and second because they are more efficient (since the code is already transferred into IL therefore only the JIT compilation takes place instead of both the IL and JIT).