Language Inter-Op

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Like the quest for the Holy Grail, the ability to seamlessly inter-op between languages has been on the forefront. On the various Windows platforms, the standard for cross language development has been the Component Object Model (COM). An entire industry was born whose sole purpose was developing COM components and ActiveX controls. Because COM is a binary standard, any language capable of consuming COM components is able to use them regardless with which language the COM component was created.

Although COM allowed for reusable components, it was far from perfect. Certain languages, such as scripting languages, could only make use of the default interface provided by the COM object. Also, it was not possible to inherit from a COM component to extend its basic functionality. To extend a binary object, developers were forced to wrap the COM component, not a very OO approach.

With the advent of .NET and IL, such barriers no longer exist. Because every language targeted at the .NET platform understands IL and the metadata of a .NET component, a new level of interoperability is born. The metadata allows inspection of a .NET component to discover the classes, methods , fields, and interfaces that it contains. The topic of metadata will be covered later in this section.

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