initialization.md

Initialization

We can initialize any component's attribute by initial binding: @init. It loads ViewModel's property once at the beginning then the property won't be synchronized by binder during user interaction. But EL evaluation's result we expect in initial binding annotation is different for attribute “viewModel” and “form”.

@init at viewModel Attribute

The first place we usually use this annotation is to assign a ViewModel to a component in viewModel attribute. When using in viewModel attribute, we should specify the full-qualified class name in a string literal in @init.

<window apply="org.zkoss.bind.BindComposer" viewModel="@id('vm') @init('foo.MyViewModel')">
</window>

The composer will resolve the string 'foo.MyViewModel' and create a object of it.

Since 9.5.0 We can use simplified syntax to init view model. Notice that the id of the view model will be 'vm' by default.

<zk>
	<div viewModel="@('foo.MyViewModel')">
		<label value="@load(vm.label)" />
	</div>
</zk>

@init at Component's Attribute

It's common to use it to initialize a component's attribute with a constant value or a ViewModel's property. The binder loads it once and doesn't synchronize it afterward during following user interaction.

    <label value="@init(vm.message)"/>

    <label value="@init(123)"/>

    <checkbox checked="@init(true)"/>

Since 9.5.0 We can use simplified syntax to initialize a component's attribute.

<label value="@(vm.message)"/>

@init at Form Binding

We can also use the initial binding on the form binding to fill in predefined value.

<div form="@id('fx') @init(vm.defaultOrder) @load(vm.order) @save(vm.order, before='compute')">

</div>

We'll describe more advanced usage with @init in section Data Binding/Form Binding.