This class provides a unified service provider for managed VSPackages. It implements IServiceProvider and takes an instance of IServiceProvider as a constructor argument.
This class supports both GUID and type based lookups. It also checks for common native implementation pitfalls, such as objects that do not implement the IUnknown interface or that require a specific IID along with a matching SID.
This class also provides debugging support in the debug version of the .NET Framework (also known as a "checked" version). Setting the tracing switch TRACESERVICE to TraceVerbose causes all service requests to be output to the debug listener.
In addition, ServiceProvider tests for certain conditions when forwarding a service request to native code. Managed code requires the IUnknown interface when resolving services, but most native queries do not. If an unmanaged service cannot be obtained through an IID of IUnknown, an additional call is made in checked builds with the SID used in place of the IID. ServiceProvider raises an assert if the SID query succeeds.
Returning the result of a successful SID query in a checked build causes a different behavior in the debug and retail builds of the VSPackage, so an assert is raised instead.
In addition to translating service requests to the COM service provider, the ServiceProvider class offers the following non-replaceable services:
Provides a way to replace the COM service provider. In many places within Visual Studio an object is first given one site, and later another, more localized site. The more localized site can be passed through to the service provider's IObjectWithSite implementation to create a single point of contact for services. (The SetSite method is ignored if the site does not implement IServiceProvider.)