Programming .NET Components, 2nd Edition

Language Independence: The CLR

The .NET CLR provides a common context within which all .NET components execute, regardless of the language in which they are written. The CLR manages every runtime aspect of the code, providing it with memory management, a secure environment to run in, and access to the underlying operating system services. Because the CLR manages these aspects of the code’s behavior, code that targets the CLR is called managed code . The CLR provides adequate language interoperability, allowing a high degree of component interaction during development and at runtime. This is possible because the CLR is based on a strict type system to which all .NET languages must adhere—all constructs (such as classes, interfaces, structures, and primitive types) in every .NET language must compile to CLR-compatible types. This gain in language interoperability, however, comes at the expense of the ability to use languages and compilers that Windows and COM developers have been using for years. The problem is that pre-existing compilers produce code that doesn’t target the CLR, doesn’t comply with the CLR type system, and therefore can’t be managed by the CLR.

To program .NET components, you must use one of the .NET language compilers available with the .NET Framework and Visual Studio. The first release of Visual Studio (version 1.0, called Visual Studio .NET 2002) shipped with three new CLR-compliant languages: C#, Visual Basic .NET, and Managed C++. The second version (version ...