jsf-2 - 为什么 id is not found when I access through tag?

Question

 <h:panelGroup id="userPanel"><f:subview rendered="#{searchView.isUser}">
    <h:commandButton value="test" action="#{searchAction.doFindUsers}"   >
        <f:ajax execute="@this" event="action" render="userPanel" />
    </h:commandButton> </f:subview></h:panelGroup>

我得到的错误是:无法在组件 j_idt26 的上下文中找到它

Answer 1

因为 <f:subview>是 NamingContainer .

另见:

• How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

---

只需使用 <h:panelGroup> ,

<h:panelGroup id="userPanel">
    <h:panelGroup rendered="#{searchView.isUser}">
        <h:commandButton value="test" action="#{searchAction.doFindUsers}">
            <f:ajax execute="@this" event="action" render="userPanel" />
        </h:commandButton>
    </h:panelGroup>
</h:panelGroup>

或<ui:fragment> (只有一点点开销)

<h:panelGroup id="userPanel">
    <ui:fragment rendered="#{searchView.isUser}">
        <h:commandButton value="test" action="#{searchAction.doFindUsers}">
            <f:ajax execute="@this" event="action" render="userPanel" />
        </h:commandButton>
    </ui:fragment>
</h:panelGroup>

或者在这个具体的例子中直接在命令按钮上(当然你的情况比这更复杂)

<h:panelGroup id="userPanel">
    <h:commandButton value="test" action="#{searchAction.doFindUsers}"  rendered="#{searchView.isUser}">
        <f:ajax execute="@this" event="action" render="userPanel" />
    </h:commandButton>
</h:panelGroup>

另见:

• Alternative to ui:fragment in JSF
• Conditional rendering of non-JSF components (plain vanilla HTML and template text)