h:未填充数据表 [英] h:datatable not populated

问题描述

这是一个与(和/或跟进)相关的问题:

This is a related (and or follow up) issue to :

在Setter之前调用的事件函数

因此，鉴于我有:

<Td>
<h:selectOneMenu id="combocarList" 
value="#{customerBean.selectedcar}"
styleClass="comboStyle"
valueChangeListener="#{customerBean.loadothercombos}"
onchange="document.forms[0].submit()"
>
<f:selectItem
    itemLabel="-----------Select--------------"
    itemValue="None" />
<f:selectItems value="#{customerBean.carsList}" />
</h:selectOneMenu>
</Td>

当用户从下拉列表中选择一个项目，并且backbean进行处理以检索工作正常的其他下拉列表的值时，将调用该事件，但是我也有一个h:datatable，这就是问题所在.这些值将不会显示.

the event is called when user selects an item from dropdown list and the backbean does the processing to retrieve values of other dropdown list which works ok , BUT i also have a h:datatable which is the problem. The values won't show.

数据表定义为:

<h:dataTable
    id="calDetails" rowClasses="oddrow,evenrow"
    headerClass="thHeading" var="car"
    value="#{cardetails.allinfo}">
    <h:column>
        <f:facet name="header">
            <h:outputText id="lblCode" value="Code"></h:outputText>
        </f:facet>
        <h:inputHidden value="#{car.code}"></h:inputHidden>
        <h:outputText id="carcodeid"
            value="#{car.code}"></h:outputText>
    </h:column>
    <h:column>
        <f:facet name="header">
            <h:outputText id="lblCode" value="Sold"></h:outputText>
        </f:facet>
        <h:inputHidden value="#{car.sales}"></h:inputHidden>
        <h:outputText id="carsalesid"
            value="#{car.sales}"></h:outputText>
    </h:column>
</h:dataTable>

我有cardetails.allinfo的setter和getter，并且我知道何时调用document.forms[0].submit()的cardetails.allinfo不为null，因为当我使用

i have setter and getters for cardetails.allinfo and i know when document.forms[0].submit() is called cardetails.allinfo is not null since as i tested it using

 <h:outputText value="#{cardetails.allinfo eq null}" />

返回false.我已经盯着看了好几个小时，看不到我的错.将不胜感激任何投入.谢谢

which returned false. I've been starring at it for hours and can't see my fault. would appreciate any input. Thanks

推荐答案

显然该列表为空.更好的调试方法是

Apparently the list is just empty. A better debug is

<h:outputText value="#{not empty cardetails.allinfo}" />

只要allinfo不为null 并且不为空，它将显示true.你也可以做

This will show true whenever the allinfo is not null and not empty. You could also do

<h:outputText value="#{cardetails.allinfo}" />

以纯文本格式查看所有列表项，如

to see all list items in plain text as represented by ArrayList#toString(). If you see [] then it's indeed empty. Otherwise if you see [com.example.Car@1234,com.example.Car@5678], then it has 2 Car items (assuming that you didn't override its toString() method to return a more human readable String representation as many starters do ;) ).

如果列表为空，则需要从数据库中调试并修复列表加载逻辑.

In case of an empty list, you'd need to debug and fix your list loading logic from the DB.

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