Chapter 17: .NET Components

Overview

Even with the great changes that Microsoft has cooked into the Common Language Runtime and the .NET Framework, there are still some basics of application design that remain constant. One of those constants is the benefit of components . Even with the advent of compiled ASP.NET pages written in multiple languages, good application design still requires the use of components.

While you may no longer gain the absolute benefits of speed seen when moving to COM components from scripted ASP pages, you can still gain the benefits of encapsulation and reusability that components provide. I don't know who came up with the adage that says, 'just because you can doesn't mean that you should', but that definitely holds true with the .NET platform when it comes to application design.

In the past, one of the main reasons for moving script code to components was to gain execution speed. Now, with pages being compiled and executed, that benefit is gone. So, does this mean that you should forego good application design and throw all code into ASP.NET pages? Just because you can doesn't mean that you should!

Components are still critical in the .NET Framework. This chapter won't go into detail about why you should use components; it will talk about how to use them. It is important to know how to build components, how to use the features of the CLR to extend components, and importantly how to deploy them.

In this chapter, we will look at building and deploying .NET components for use within ASP.NET applications. Specifically, you will look at:

• Writing business objects using the .NET Framework

• Creating a class in one language, and then inheriting from that class in a different language

• Using COM+ Services, such as transactions, from within .NET components

• Deploying components in .NET