You need to use the Phidget Manager for that. You can find a code sample for the manager in C#
here.
This example will print a line to the console for each channel it sees. So if you're using a 1012, you'll get 16 lines for the outputs and 16 lines for the inputs. If you have multiple Phidgets, you can various properties to figure out which Phidget they belong to. In this example "ManagerAttachEventArgs e" contains this information (e.g. e.Channel.DeviceSerialNumber).