Binding Properties

Target

Binding target is a special type of reference that points to where the evaluation result of binding expression will be written when the binding is processed. Check the binding target section for details.

Expression

This is an Iotellect Expression that is evaluated every time a binding is processed. The evaluation result is stored in the binding target. See Binding Expression for details.

Activator

This is a reference that points to some context event or property that will trigger the processing of the binding. The Activator parameter is available only when On event parameter is enabled. See Binding Activator for details. In case an Activator isn't specified and the binding still has an option to evaluate, see On Event for more information.    

Condition

Condition is an Iotellect Expression that is evaluated first after binding activation. If this expression results to false, the binding execution is skipped.

On Startup

When this parameter is enabled, the binding is processed every time the binding set is started.

On Event

When this parameter is enabled and an Activator is specified, the binding is processed whenever there's a changes in the property the activator refers to. If the Activator refers to an event, the binding will be processed when the event fires. If On event is enabled and an Activator is not specified, the binding will be automatically processed: The binding's Expression includes references, pointing to one or more variables. A change in any of these variables will cause the binding to run.

For example, let's take the following binding, and say that no Activator was specified for it:

  Target: users.admin.deviceservers.ds1.devices.thermostat:temperature$temperature  

  Expression: {user.admin.devices.sensor:temperatureField:value} + {user.admin.devices.sensor:temperatureAdjustmentField:value}

This binding has an expression which takes the value from a form field called temperatureField, and adds it to the value of the temperatueAdjustmentField form field. The end result is then written to the Target. Now, since this binding doesn't have an Activator but On event is enabled for it, the binding is processed whenever the user changes one of the form fields specified in the Expression.

Periodically

If this parameter is enabled, the binding will be processed periodically.

Period

Interval between binding processing sessions. This parameter may be changed only if Periodically is turned on.

Queue

Name of binding target processing queue. Bindings engine guarantees that targets of bindings that belong to same queue will be accessed sequentially, in the same order the bindings were executed.

Queue parameter is not supported in some binding evaluation environments, e.g. in model bindings.