Chapter 3. The .NET Framework

The .NET Framework is the next iteration of Microsoft’s platform for developing component-based software. It provides fundamental advances in runtime services for application software. It also supports development of applications that can be free of dependencies on hardware, operating system, and language compiler.

This chapter provides an overview of the architecture of the .NET Framework and describes the base features found in the core of its class library.

Common Language Infrastructure (CLI) and Common Language Runtime (CLR)

At the heart of the .NET Framework is a new mechanism for loading and running programs and managing their interactions. This mechanism is described in the Common Language Infrastructure (CLI), a specification for a runtime environment that allows software components to:

  • Pass data between each other without regard to the programming language in which each component is written

  • Execute on different operating systems and on different hardware platforms without having to recompile the high-level source code (a low-level compilation still automatically occurs on the target platform, as will be discussed in this chapter)

Although the CLI specification was created by Microsoft, it has since been submitted to the ECMA standards organization (, which now has responsibility and control over it.

The CLI is just a specification—it has to be implemented in order to be useful. An implementation of the CLI is known as ...

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