Ultra Light Client Guide and Reference


How ULC compares with common widget protocol

The most significant difference between ULC and CW is in its handling of system events. You register interest in a ULC event by sending a message to the widget that would signal the event. CW callbacks are not used.

For example, to register for the action event of a UlcButton instance, send the message #ulcWhenActionSend: aDirectedMessage to the button. At run time, aDirectedMessage is sent whenever the action event occurs. If the event has additional objects associated with it, nil parms of aDirectedMessage are replaced with those associated objects, in sequence, when the event occurs.

All event registration methods implemented in a given widget are categorized under ULC-API-Events.

Other differences from CW


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