Cannot pass a parameter without @BindingParam

    <nodom viewModel="@('org.zkoss.mvvm.parameters.ParametersVM')">

    <grid id="outergrid" width="700px" model="@bind(vm.items)">
        <columns>
            <column label="index"/>
            <column label="name"/>
            <column label="action" width="300px"/>
        </columns>

        <template name="model" var="item">
            <row>
                <label value="@bind(itemStatus.index)"/>
                <label value="@bind(item)"/>
                <hbox>
                    <button label="Index" onClick="@command('showIndex', index=itemStatus.index)"/>
                    <button label="Delete" onClick="@command('delete', item=item)"/>
                </hbox>
            </row>
        </template>
    </grid>
        <label value="@load(vm.message)"/>
    </nodom>