Implementing the Primary Interface for a Method Provider
Because other providers use IWbemServices, the interface contains many methods that are irrelevant to a pure method provider. Your pure method provider should supply a stub implementation that returns WBEM_E_PROVIDER_NOT_CAPABLE for all of other IWbemServices methods besides ExecMethodAsync. However, many method providers also serve as instance or class providers. Combination method and instance providers must support more of the IWbemServices methods.