h：selectOneMenu在p：dataTable中不提交其值 [英] h:selectOneMenu in p:dataTable doesn't submit its value

问题描述

我有一个关于selectOneMenu和设置值的问题。我有一个Object SampleDesc和ID，Text和一个 List< SampleDescValues> 。对于每个数据行，Text是输出标签，选择一个菜单值是 List< SampleDescValues> 。
XHTML：

I have a question about selectOneMenu and settting the values. I have an Object SampleDesc that has and ID, Text, and a List<SampleDescValues>. For each datatable row the Text is the output label and the select one menu values are the List<SampleDescValues>. XHTML:

    <h:panelGroup id="tables">
    <p:dataTable resizableColumns="true" 
             var="sampleDesc" id="SampleDescTable" rowIndexVar="rowIndex"
                     value="#{sampleBean.sampleDescList.list}" 
                     rendered="#{sampleBean.sampleDescList.list.size() gt 0}">
            <p:column>
                    <h:outputLabel value="#{sampleDesc.sampleDescText}"/>
                </p:column>
        <p:column>
            <h:selectOneMenu required="#{sampleBean.sampleDescList.list.size() gt 0}" converter="#{sampleDescValueConverter}" 
                                                         id="SampleDescValue" value="#{sampleBean.selectedSampleDescList.get(rowIndex)}">                                                         
                <f:selectItem itemLabel="Select One" itemValue="#{null}"/>
                            <f:selectItems value="#{sampleDesc.sampleDescValues}" var="sdv" 
                                       itemLabel="#{sdv.sampleDescValuesText}" itemValue="#{sdv}" />

                        </h:selectOneMenu>
                </p:column>    
        </p:dataTable>
</h:panelGroup>   

我有转换器设置，它的工作原理是因为将它设置为单个SampleDescValue，并设置值。

I have the converter setup and it works because ive set it to a single SampleDescValue and it set the value.

问题是当我从数据库中尝试使用Sample填充表单时，只能在无限数量的selectonemenu的

The problem is when i try and populate the form with a Sample from the database it can only set one of the dropdowns when there could be an infinite number of selectonemenu's

我将所选值设置为 private List< SampleDescValue> selectedSampleDescList;

当我尝试提交它什么也不做，当datatable没有呈现时它工作。

When i try and submit it does nothing, it works when the datatable is not rendered.

推荐答案

您的菜单值是错误的：

<h:selectOneMenu value="#{sampleBean.selectedSampleDescList.get(rowIndex)}">

无法执行设置操作在这个EL表达式上。

It's not possible to perform a set operation on this EL expression.

改用括号符号：

<h:selectOneMenu value="#{sampleBean.selectedSampleDescList[rowIndex]}">

请注意，这需要非空值 selectedSampleDescList 。因此，请确保您已经使用新的ArrayList（）进行了正确的初始化。 EL不会为你做的。它只会使用 List＃add（index，object）方法设置列表项。

Note that this expects a non-null selectedSampleDescList. So make sure that you've already properly initialized it with a new ArrayList<>() beforehand. EL won't do that for you. It will only set the list items using List#add(index, object) method.

• 我们的EL wiki页面

• Our EL wiki page

与具体问题无关 p>

Unrelated to the concrete problem, this expression

#{sampleBean.sampleDescList.list.size() gt 0}

可以简化如下

#{not empty sampleBean.sampleDescList.list}

这是始终 c $ c> c c c c <在这一点上评估 true 。只需直接使用 required =true

And this is unnecessary in the required attribute of the <h:selectOneMenu> as it would always evaluate true at that point. Just use required="true" directly instead.

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