何时在jsf组件中使用:(冒号)进行渲染

问题描述

我已经读过，我们应该使用:(冒号)来渲染其他形式的组件.但就我而言

i have read that, we should use :(colon) to render components in other form. but in my case

<h:form id="form">
    <p:growl id="messages"></p:growl>
    <p:dataTable var="e" value="#{employees.eList}" id="elist1"
        editable="true">
        <f:facet name="header">
        In-Cell Editing
    </f:facet>
        <p:ajax event="rowEdit" listener="#{employees.onEdit}" update=":form:messages"/>

        <p:ajax event="rowEditCancel" listener="#{employees.onCancel}" />

        <p:column headerText="name" style="width:30%">
            <p:cellEditor>
                <f:facet name="output">
                    <h:outputText value="#{e.name}" />
                </f:facet>
                <f:facet name="input">
                    <h:inputText value="#{e.name}" style="width:100%" />
                </f:facet>
            </p:cellEditor>
        </p:column>
..........   ...........
</p:datatable>

我想从数据表组件更新消息(抱怨)，为什么我必须使用冒号update =:form:messages"

i want to update messages(growl) from datatable component why i have to use colon update=":form:messages"

推荐答案

相对于实现 NamingContainer接口.如您在链接的Javadoc中所看到的，至少是所有UIForm和UIData组件. <h:form>就是这样的. <p:dataTable>是另一个.

All relative client IDs (the ones not starting with :) are searched relative to the parent component which implements the NamingContainer interface. As you can see in the linked javadoc, that are at least all UIForm and UIData components. The <h:form> is such one. The <p:dataTable> is another one.

在特定情况下，<p:ajax>包含在<p:dataTable>中.因此，<p:ajax update="messages">将在<p:dataTable>的上下文中查找ID为messages的子组件.但是，由于没有任何内容，因此找不到任何内容.实际上，您实际上需要使用绝对客户端ID，因为它在当前NamingContainer父对象的上下文之外.

In your particular case, the <p:ajax> is enclosed in <p:dataTable>. So, the <p:ajax update="messages"> would look for a child component with ID messages inside the context of <p:dataTable>. However, since there is none, it won't find anything. You actually need to use an absolute client ID instead because it's outside the context of the current NamingContainer parent.

• 如何找出要进行Ajax更新/渲染的组件的客户端ID?找不到表达式为"foo"的组件；引用自"bar"

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