h：dataTable复合组件，cc.attrs.var，IllegalArgumentException

问题描述

我正在尝试创建自己的数据表，如原理图。问题是，当使用的时候， cc.attrs.var 会抛出一个IllegalArgumentException异常。所以我想知道我如何可以使用如原型的var属性。

I'm trying to create my own dataTable like the primefaces one. The problem is that cc.attrs.var when used throws a IllegalArgumentException. So I'm wondering how I can have the var attribute like Primefaces.

<cc:interface>
    <cc:attribute name="value"/>
    <cc:attribute name="var"/>
    <cc:attribute name="styleClass"/>
</cc:interface>

<cc:implementation>

    <div>Previous</div>
    <div>Next</div>

    <h:dataTable value="#{cc.attrs.value}" var="#{cc.attrs.var}" styleClass="#{cc.attrs.styleClass}">
        <ui:insert/>
    </h:dataTable>

</cc:implementation>

推荐答案

根据 javadoc，不允许在 var 属性中有EL表达式。

As per the UIData#setValueExpression() javadoc, it's not allowed to have an EL expression in var attribute.

你最好的办法是创建一个支持组件，您可以手动评估并设置组件在 postAddToView 事件中绑定到< h：dataTable> 。

Your best bet is to create a backing component wherein you manually evaluate and set the var attribute of the UIData component bound to <h:dataTable> during the postAddToView event.

<cc:interface componentType="yourTableComposite">
    <cc:attribute name="value" />
    <cc:attribute name="var" />
</cc:interface>
<cc:implementation>
    <f:event type="postAddToView" listener="#{cc.init}" />

    <h:dataTable binding="#{cc.table}" value="#{cc.attrs.value}">
        <cc:insertChildren />
    </h:dataTable>
</cc:implementation>

@FacesComponent("yourTableComposite")
public class YourTableComposite extends UINamingContainer {

    private UIData table;

    public void init() {
        table.setVar((String) getAttributes().get("var"));
    }

    public UIData getTable() {
        return table;
    }

    public void setTable(UIData table) {
        this.table = table;
    }

}

请注意，我修复了< ui：insert> 为< cc：insertChildren> 。 < ui：insert> 只能在< ui：composition> / < ui：decorate> 。

Note that I fixed the <ui:insert> to be <cc:insertChildren>. The <ui:insert> can only be used in <ui:composition>/<ui:decorate>.

• Initialize a composite component based on the provided attributes
• How does the 'binding' attribute work in JSF? When and how should it be used?

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