A provider connection point object always has a default interface that is used to establish a connection with consumers. An instance of the default interface is retrieved by calling the ProviderConnectionPoint.GetObject(System.Web.UI.Control) method on a System.Web.UI.WebControls.WebParts.ProviderConnectionPoint object.

However, some provider controls will implement multiple interfaces to provide to consumers as part of a connection. These interfaces, which are not the default ones used to establish a connection, are called secondary interfaces. The ProviderConnectionPoint.GetSecondaryInterfaces(System.Web.UI.Control) method provides a way to return a collection of references to the secondary interfaces, just as the ProviderConnectionPoint.GetObject(System.Web.UI.Control) method returns a reference to the default interface.