使用的EL EX pression传递一个组件ID在JSF复合组件 [英] Use an EL expression to pass a component ID to a composite component in JSF

问题描述

问题：我正在传递的EL前pression到复合部件，但在EL前pression正在从复合部件内评估，而不是之前。其用意是使EL前pression计算为一个字符串被发送到复合部件

Problem: I am passing an EL expression to a composite component, but the EL expression is being evaluated from inside the composite component, rather than before. The intention being that the EL expression evaluates to a string with is sent to the composite component.

我有一个复合成分， MenuTable ：

<cc:interface>
    <cc:attribute name="model" type="nz.co.tradeintel.web.MenuTable"/>
    <cc.attribute name="updateId" /> 
</cc:interface>

<cc:implementation>
    <h:panelGroup id="menuTable">
    <table>
        <ui:repeat id="repeat1" value="#{cc.attrs.model.rows}" var="row">
            <tr>
            <ui:repeat id="repeat2" value="#{row.contents}" var="entry">
                <td>
                    <p:commandLink action="#{cc.attrs.model.setSelected(entry)}" update="#{cc.attrs.updateId}" value="#{entry.toString()}"/>
                </td>
            </ui:repeat>
            </tr>
        </ui:repeat>
    </table>
    </h:panelGroup>
</cc:implementation>

的意图是，我通过一个绝对的组件ID为属性 updateId 是这样的：

<p:PanelGroup id="updatingPanel">
    <!-- Lots of components.-->
</p:PanelGroup>
<custom:MenuTable updateId="#{component.clientId}:updatingPanel" model="#{menuBackBean.menuTable}" />  

现在的问题是，在EL EX pression为 updateId 从＆LT的范围进行评估;号码：commandLink /＆GT ; 复合组件中，我也得到了以下错误：

The problem is, the EL expression for the updateId is evaluated from the scope of the <p:commandLink /> within the composite component, and I get the following error:

javax.faces.FacesException: Cannot find component with identifier ":j_idt37:j_idt39:updatingPanel:j_idt61:repeat1:0:repeat2:0:j_idt65:updatingPanel" referenced from "j_idt37:j_idt39:updatingPanel:j_idt61:repeat1:0:repeat2:0:j_idt65".

注：JSF认为我想更新与组件和ID updatingPanel 是的在的复合成分

为什么EL EX pression不是从外部范围评估：＆LT;自定义：MenuTable /＆GT;

Why is the EL expression not evaluated from the outer scope: <custom:MenuTable/>?

有一些相关的答案，但我不理解他们，如的这个。

There are a few related answers, but I don't understand them, such as this one.

使用Mojarra 2.1.15

Using Mojarra 2.1.15

推荐答案

EL EX pressions没有评估目前的组件的内置，但此刻的属性进行访问。换句话说，他们的运行的而不是构建时的。该＃{组件} 指的是<一href="http://docs.oracle.com/javaee/6/api/javax/faces/component/UIComponent.html#getCurrentComponent%28javax.faces.context.FacesContext%29"相对=nofollow> 电流的此刻的EL EX pression评估UI组件，这是在特定情况下，＆LT;电话号码： commandLink＆GT; 。这也解释了不同的结果。

EL expressions are not evaluated at the moment the component is built, but at the moment the attribute is accessed. In other words, they're runtime and not buildtime. The #{component} refers to the current UI component at the moment the EL expression is evaluated, which is in your particular case the <p:commandLink>. That explains the different outcome.

您需要处理这个不同，而无需使用＃{组件} 。方法之一是

You need to approach this differently, without using #{component}. One of the ways is

<p:panelGroup binding="#{updatingPanel}">
    ...
</p:panelGroup>
<custom:MenuTable ... updateId=":#{updatingPanel.clientId}" />

如果仍然无法正常工作，那么请确保您不使用＆LT; H：形式prependId =假＆GT;

If that still doesn't work, then make sure that you don't use <h:form prependId="false">.

• <一个href="http://stackoverflow.com/questions/8634156/how-to-reference-components-in-jsf-ajax-cannot-find-component-with-identifier/8644762#8644762">How引用组件的JSF AJAX？无法找到标识符QUOT组成部分;富＆QUOT;鉴于
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