We are now done with our controller. The controller will now work and control the actuator based on input from the sensor, if both have been registered in the same registry, using the same location tags.

There are two issues we have not covered in this chapter, but need considering in a real-life scenario:

• Provisioning: The next chapter will introduce this concept. It will allow the owner of a device to control who can do what with it. Provisioning also handles a transfer of ownership of devices.
• Decommissioning: When a device is no longer to be used on the internet, it should be unregistered from the Thing Registry, so that others cannot find it and try to interact with it. A device unregisters itself by calling the Unregister() method on the ThingRegistryClient object instance. A controller may also need to test multiple devices in the search result, assuming some of them might not be valid anymore.