Replaces or enhances the behavior of Microsoft Exchange when recipient names typed by the user are being resolved to their address book entries.
See IExchExtMessageEvents : IUnknown.
HRESULT OnCheckNames(
LPEXCHEXTCALLBACK lpeecb
);
Microsoft Exchange calls the IExchExtMessageEvents::OnCheckNames method when it is about to resolve unresolved names.
If an error occurs, OnCheckNames should display an error message and return an error. Microsoft Exchange will not continue to check names, nor will it display an error message, but will stop the user action that caused the check names operation. This method should call the IExchExtCallback::GetObject method to determine the message identifier of the item being displayed and its container. The container is usually a folder, but it can also be a message or an information store.
IExchExtCallback::GetObject, IExchExtMessageEvents : IUnknown