Object Registry

This sections explains a couple of utility classes that can be used by host applications.

Object Registry

Often, the host application just needs to create an instance of all the extension implementations registered with a particular extension point.

In the example above, we explicitly went through the plug-in registry object model to illustrate how the various classes interact. However, to facilitate this common use case, there’s a helper class, called ObjectRegistry<TExtensionAttribute, TExtensionType>. This class allows the host application to quickly create a list of extension implementation objects as follows:

• C#

            ObjectRegistry<MessageTransmitterAttribute, IMessageTransmitter> objectRegistry =
new ObjectRegistry<MessageTransmitterAttribute, IMessageTransmitter>(pluginRegistry);

            IMessageTransmitter[] messageTransmitters = objectRegistry.CreateObjects();
            #endregion ObjectRegistry

ObjectRegistry<TExtensionAttribute, TExtensionType> is a generic class accepting two template parameters:

• TExtensionAttribute: the extension attribute type defining the extension point
• TExtensionType: the common interface, that all extensions for this extension point must implement. The CreateObjects method simply instantiates all the extension implementations and returns them in a typed array.

Note

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