ZK Component Reference/Containers/Fragment

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Fragment

• Demonstration: N/A
• Java API: Fragment
• JavaScript API: Fragment
• Style Guide: N/A

Employment/Purpose

Fragment is a ZK component that let developers combine native HTML elements with ZK data binding syntax to make the static page to be dynamic.

Example

Data Binding

By binding the properties of ViewModel to a Fragment component, you can use the ZK MVVM data binding syntax on the native HTML elements.

<zk>
    <fragment viewModel="@id('vm') @init('org.zkoss.zktest.test2.F85_ZK_3681_Command_VM')"
              status="@bind(vm.status)"><![CDATA[
        <div>
            <input type="checkbox" onchange="@command('onCheck', checked=event.checked)" />
            Check this checkbox: <span textContent="@load(status)"/>
        </div>

        <div>
            <button onclick="@global-command('callGlobal', text='Hello', num=1)">Call global (1)</button>
            <button onclick="@global-command('callGlobal', text='World', num=2)">Call global (2)</button>
        </div>
    ]]></fragment>
</zk>

Shadow Elements

In this example, we use forEach and if tags together for condition and collection rendering.

<zk>
    <fragment viewModel="@id('vm') @init('org.zkoss.zktest.test2.F85_ZK_3681_Shadow_VM')"
        issues="@bind(vm.issues)"><![CDATA[
        <section>
            <h1>My Issue List</h1>
            <ul>
                <forEach items="@load(issues)">
                    <!-- There's a pre-defined variable "each" for convenience. -->
                    <li>
                        <!-- @bind(each) is wrong because each is just a temp variable in loops. -->
                        <input type="checkbox" checked="@load(each.isDone)" />
                        <if test="@load(each.isDone)">
                            <strike>[<span textContent="@load(each.id)"/>]
                            <span textContent="@load(each.description)"/></strike>
                        </if>
                        <!-- No else for now. -->
                        <if test="@load(!each.isDone)">
                            [<span textContent="@load(each.id)"/>]
                            <span textContent="@load(each.description)"/>
                        </if>
                    </li>
                </forEach>
            </ul>
        <section>
    ]]></fragment>
</zk>

Validation

Here we use form binding and a form validator to validate the form once for all.

<zk>
    <fragment viewModel="@id('vm') @init('foo.BarVM')" validationMessages="@id('vmsgs')"
     form="@id('fx') @load(vm.currentUser) @save(vm.currentUser, before='submit') @validator('formBeanValidator', prefix='p_')"
     name="@bind(fx.name)" nameerror="@bind(vmsgs['p_name'])"><![CDATA[
     <input type="text" value="@bind(name)"/><span textContent="@load(nameerror)"/>
     <button onclick="@command('submit')">Submit</button>
    ]]></fragment>
</zk>

This component also provides a new @jsvalidator(validation_function_name) syntax to validate at client-side by evaluating your custom JavaScript function.

<zk>
    <fragment viewModel="@id('vm') @init('foo.BarVM')" someprop="@bind(vm.prop1)"><![CDATA[
        <input type="text" value="@bind(someprop) @jsvalidator('validateExample')"/>
        <span textContent="@load(vmsgs['foo'])"/>
        <script type="text/javascript">
        // @param val The value of user input
        // @param vmsgs A object of validation message holder
        // @return boolean true if it is valid
        function validateExample(val, vmsgs) {
            var isValid = someValidationProcess(val);
            vmsgs['foo'] = isValid ? '' : 'Invalid value';
            return isValid;
        }
        </script>
    ]]></fragment>
</zk>

Properties

• content: specify the content of this component.
• src: specify the URI of an external content file. The file encoding is assumed to be UTF-8.

Supported Events

Name	Event Type
onRecover	Event: Event Represents an event sent back to the server caused by an offline recovery.

Supported Children

None

Use Cases

Version	Description	Example Location

Version History

Version	Date	Content
8.5	2017/09/21	Add the new Fragment component