如何有条件地呈现 f:selectItem 标签? [英] How to conditionally render an f:selectItem tag?

问题描述

如何为 标记指定条件呈现.我需要根据特定用户的状态显示 选项.

How can I specify a conditional rendering for an <f:selectItem> tag. I need to display <f:selectItem> options according to a specific user's status.

例如，我想要这样的东西:

For example, I wanted something like:

<f:selectItem itemLabel="Yes! I need a girlfriend!"
             rendered="false(or some boolean condition)"
             itemValue="o1"/>

推荐答案

不支持 rendered 属性.您最接近的赌注是 itemDisabled 属性，它仍然显示该项目，但使其无法选择.这在 中也受支持.

The <f:selectItem> does not support the rendered attribute. Your closest bet is the itemDisabled attribute which still displays the item, but makes it unselectable. This is also supported in <f:selectItems>.

在 的情况下，您可以添加一些 CSS 来隐藏禁用的项目.

In case of <p:selectOneMenu> you can then just add some CSS to hide disabled items.

<p:selectOneMenu ... panelStyleClass="hideDisabled">
    <f:selectItem itemValue="1" itemLabel="one" />
    <f:selectItem itemValue="2" itemLabel="two" itemDisabled="#{some.condition}" />
    <f:selectItem itemValue="3" itemLabel="three" />
</p:selectOneMenu>

.ui-selectonemenu-panel.hideDisabled .ui-selectonemenu-item.ui-state-disabled {
    display: none;
}

在 的情况下，您更依赖于浏览器是否支持通过 CSS 隐藏禁用的选项:

In case of <h:selectOneMenu> you're more dependent on whether the webbrowser supports hiding the disabled options via CSS:

<h:selectOneMenu ... styleClass="hideDisabled">
    <f:selectItem itemValue="1" itemLabel="one" />
    <f:selectItem itemValue="2" itemLabel="two" itemDisabled="#{some.condition}" />
    <f:selectItem itemValue="3" itemLabel="three" />
</h:selectOneMenu>

select.hideDisabled option[disabled] {
    display: none;
}

服务器端的替代方法是在单个 周围引入 JSTL 以有条件地将其添加到视图中，例如这(确保您了解 JSTL 在 JSF 中的工作方式:JSF2 Facelets 中的 JSTL...有意义吗?):

The server side alternative is to bring in a JSTL <c:if> around the individual <f:selectItem> to contitionally add it to the view like this (make sure you're aware of how JSTL works in JSF: JSTL in JSF2 Facelets... makes sense?):

<f:selectItem itemValue="1" itemLabel="one" />
<c:if test="#{not some.condition}">
    <f:selectItem itemValue="2" itemLabel="two"  />
</c:if>
<f:selectItem itemValue="3" itemLabel="three" />

或者，您可以根据计算出的条件简单地在支持 bean 中动态填充 List，并将其与 绑定.

Or, you could simply dynamically populate a List<SelectItem> in the backing bean based on the calculated conditions and bind it with <f:selectItems>.

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