| <library xmlns="http://localhost/openlaszlo/lzx" | |
| xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | |
| xsi:schemaLocation="http://localhost/openlaszlo/lzx ./../../../lzx.xsd"> | |
| <!--- The sender in Laszlo's point-to-point event system. | |
| Events underly most of the functionality in OpenLaszlo applications. Unlike events in similar systems, OpenLaszlo's events are point-to-point, meaning that there is no general broadcast mechanism for events, and events do not trickle up or down the instance hierarchy. Instead, objects called <handler>s use LzDelegate.register() to register to receive events. | |
| An event is implicitly declared for every attribute of a class or instance and sent when that attribute is changed. So, for instance, if a class has an attribute foo, you can receive events when foo changes by registering for the onfoo event. | |
| Events are sent with a single argument, which usually conveys information about the property that changed. The default behavior of the LzEventable.setAttribute() method is to set the named property and send the event called "on" + property. This is general mechanism that updates constraints in a OpenLaszlo programs. For instance, when a view changes its x position, it sends the event onx with the new value for its x property. | |
| Example: | |
| <handler name="onavalue" reference="eventSender" args="v"> | |
| this.setAttribute('x' , v); | |
| </handler> | |
| --> | |
| <class name="event" extends="false"> | |
| <!--- The name of the event --> | |
| <attribute name="name" type="string" /> | |
| </class> | |
| </library> |