Reference Binding

This article is out of date, please refer to zk-mvvm-book/8.0/data_binding/reference_binding for more up to date information.

• Available for ZK:
• 

Since 6.0.1

Make an expression reference

Reference binding allows us to reference an EL expression with a customized name. We can use this reference in another EL expression nested in the component that is binded to this reference. Typically, we use reference binding to shorten expressions or to modularize the view.

Steps to use this feature:

1. Bind a custom attribute on a component with @ref.
2. Use the custom attribute in other EL expressions that are nested in children components

---

Basic usage example

<window apply="org.zkoss.bind.BindComposer" 
	viewModel="@id('vm') @init('foo.MyVM')">
	<vlayout p="@ref(vm.person)">
		<hlayout>
			First Name: <textbox value="@bind(p.firstName)" />
		</hlayout>
		<hlayout>
			Last Name: <textbox value="@bind(p.lastName)" />
		</hlayout>
	</vlayout>
</window>

As shown in the example above, we add a reference @ref to vm.person with a name p to vlayout. This way, p inside the vlayout can be used by other EL expressions.

Modularize view example

<window apply="org.zkoss.bind.BindComposer" 
	viewModel="@id('vm') @init('foo.MyVM')">
	<include p="@ref(vm.person1)" src="person.zul"/>
	<include p="@ref(vm.person2)" src="person.zul"/>
</window>

Modularize view example - person.zul

<vlayout>
	<hlayout>
		First Name: <textbox value="@bind(p.firstName)"/>
	</hlayout>
	<hlayout>
		Last Name: <textbox value="@bind(p.lastName)"/>
	</hlayout>
</vlayout>

In the example above, we have a veiw - person.zul which binds components to p.firstName and p.lastName. This view could be reused by other views that provides a p reference.

Version History

Version	Date	Content
6.0.1	May 2012	The new reference-binding feature.