如何有条件地渲染< f:facet&gt ;? [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属性能起作用:

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

但是页脚仍然呈现，内容为空.似乎facet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.

什么是正确的方法?

推荐答案

我能够通过将facet换成attribute来解决此问题.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>

也不是

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

也不是

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

---

工作"是指:

在#{message}为空或null时，提供否页脚—不仅是空白页脚&mdash ;，否则，将正确显示具有指定文本的页脚."

---

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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