Executing Managed Code

Components (shown in gray) of the Common Language Runtime (CLR) load and execute applications.

(1) The Class Loader loads the application’s assembly into memory. The assembly consists of Microsoft Intermediate Language (MSIL) code, and metadata describing the software components in the application’s assembly and the other components that the application requires.

Using the application assembly’s metadata, the Class Loader then attempts to load the supporting assemblies of any components the application requires. For example, it might load an assembly containing the graphical user interface (GUI) controls required by a desktop application. The Class Loader uses the Versioning Policy (specified by either the application’s developer or the system administrator) to determine which versions of the supporting assemblies to load. For example, a Versioning Policy might dictate that only specific versions of the GUI components must be used, even if more recent versions are available. This eliminates the component version problem that was so common with Windows applications in the past.