Aurelia获取Repeat.for转换后的数组长度并在if.bind中使用

Question

如何在repeat.for中获得名为falilid的过滤数组的长度，然后将此长度用作.files-message div的条件？如果此长度为undefined, false, 0, null等，则应显示消息，否则应将其隐藏。我尝试为.white-box编写ref，尝试绑定新的属性，然后在条件中使用它。但没帮上忙。有什么建议吗？寻找你的帮助

  <div class="elem" if.bind="!elem.children.length">
        <div class="files-wrapper">

        <div class="form-inline">
            <div class="white-box" repeat.for="fail of failid | filterOnProperty:'elemId':elem.parent.id | filterOnProperty:'remove':false" >
                <elem-fail if.bind="fail != null" fail.two-way="fail" on-fail-eemaldatud.call="failRemoved(fail)"></elem-fail>
            </div>

            <div class="files-message">Some  message</div>

            <editable-file-upload liik-kl-oid.bind="elem.parent.id" on-file-uploaded.call="failUploaded(liik.parent.id, subelem.id, failiViitedId, file)">Lae üles</editable-file-upload>

        </div>

    </div>
</div>

Answer 1

您可以在parent属性中创建筛选数组，然后在repeat.for和if.bind中使用此属性。例如：

<div class="form-inline" ref="myForm" fails.bind="failid | filterOnProperty:'elemId':elem.parent.id | filterOnProperty:'remove':false">

  <div class="white-box" repeat.for="fail of myForm.fails">
    <elem-fail if.bind="fail != null" fail.two-way="fail" on-fail-eemaldatud.call="failRemoved(fail)"></elem-fail>
  </div>

  <div class="files-message" if.bind="myForm.fails.length">Some  message</div>

  <editable-file-upload liik-kl-oid.bind="elem.parent.id" on-file-uploaded.call="failUploaded(liik.parent.id, subelem.id, failiViitedId, file)">Lae üles</editable-file-upload>

</div>

希望这能有所帮助！