Binding Expression

Widget binding expressions are very similar to server binding expressions. However, binding expressions in widgets may include two types of references:

• Standard references that point to context variables or functions, their fields or properties, and

• Component references that point to properties of widget components.

A component reference points to a property of a widget component (e.g. the text of a Label). It has the following format:

form/component:property

form is the name of the schema used to identify component references. It tells the expression language processor to resolve the reference according to the component, as opposed to a standard reference. Component references must always start with form/.

component is the name of the widget component you want to work with. The component name is shown in Resource Window and in the title of the Component Properties Window when the component is selected in Widget editor.

property is the name of a specific property within the component. Property names can be found in the description of properties of every widget component. Property part of a component reference is optional. If it is omitted, the reference points to the default property of the component.

Type of property, i.e. type of value returned by a component property reference, may be found in the description of this property in the components reference.

{form/userNameField:}

{form/userNameField:text}

Both of these two references resolve to the text currently contained in userNameField (assuming that's a text field). The first variant points to the default property of component, which is text, and the second one names it explicitly (:text).

{form/slider1:value} * 100

This expression will resolve to a number that equals to the value property (which is a default property and thus is not explicitly specified) of the Slider component called slider1, multiplied by 100.

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