我如何有条件地渲染一个 <f:facet>? [英] How do I conditionally render an <f:facet>?

问题描述

我希望能够有条件地从 PrimeFaces 面板元素中省略页脚:

I would like to be able to conditionally omit a footer from a PrimeFaces panel element:

<p:panel header="some text">
    <f:facet name="footer">
        #{message}
    </f:facet>
    <!-- ... -->
</p:panel>

我希望 rendered 属性会起作用:

I hoped that the rendered attribute would work:

<p:panel header="some text">
    <f:facet name="footer" rendered="#{!empty message}">
        #{message}
    </f:facet>
    <!-- ... -->
</p:panel>

但页脚仍然呈现，内容为空.facet 似乎没有 rendered 属性:http://www.jsftoolbox.com/documentation/help/12-TagReference/core/f_facet.html.

But the footer is still rendered, with empty content. It appears that facet does not have the rendered attribute: http://www.jsftoolbox.com/documentation/help/12-TagReference/core/f_facet.html.

这样做的正确方法是什么?

推荐答案

我能够通过将 facet 换成 attribute 来解决这个问题.总结一下:

I was able to solve this by swapping the facet out for an attribute. To summarize:

<p:panel ...>
    <f:attribute name="footer" value="#{message}"/>
    <!-- ... -->
</p:panel>

但这不起作用

<p:panel footer="#{message}">
    <!-- ... -->
</p:panel>

这也没有

<p:panel ...>
    <f:facet name="footer">#{message}</f:facet>
    <!-- ... -->
</p:panel>

也不是这个

<p:panel ...>
    <f:facet name="footer">
        <h:outputText value="#{message}" rendered="#{!empty message}"/>
    </f:facet>
    <!-- ... -->
</p:panel>

<小时>

我所说的作品"是指:

"渲染 no 页脚 — 不只是空页脚 — 当 #{message} 为空或 null 时；否则，正确使用指定的文本呈现页脚."

---

by "works" I mean:

"renders no footer — not just an empty footer — when #{message} is empty or null; otherwise, correctly renders the footer with the specified text."

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