在操作(命令按钮)之前触发preRenderView-Event [英] preRenderView-Event triggered before an action (commandbutton)

问题描述

我的preRenderView-Event有点麻烦.我的页面还使用CommandButton提交数据，但不幸的是，总是在调用button动作之前调用preRenderView-Event.

I am in a little bit of trouble with my preRenderView-Event. My page also uses a commandbutton to submit data but unfortunately the preRenderView-Event is always called before the buttons action is invoked.

preRenderView-Event负责从服务加载数据.由于页面很简单，不需要存储任何数据，因此我不需要任何Session或ViewScoped-Beans.

The preRenderView-Event is responsible for loading data from a service. Since the page is simple and doesnt have to store any data I dont need any Session or ViewScoped-Beans.

据我了解，该事件是在渲染-响应-阶段"中调用的，并且按钮中的操作应该更早发生.

As far as I understood the event is called in the Render-Response-Phase and the action in the button should happen somewhat earlier.

<h:body>
    <f:metadata>
        <f:viewParam name="id" value="#{bean.id}" converter="converter.SetOfLongConverter"/>
        <f:event type="preRenderView" listener="#{bean.initializeData}" />
    </f:metadata>

    <ui:composition template="/META-INF/templates/myTemplate.xhtml">
        <ui:param name="title" value="#{bean.title}"/>
        <ui:define name="content">
            <h:outputText value="#{bean.description}" />
            <h:form>
                    <h:panelGrid columns="2">
                        <h:outputLabel value="Model" for="model" />
                        <h:inputText id="model" value="#{bean.model}" />
                        <h:outputLabel value="Manufacturer" for="manufacturer" />
                        <h:inputText id="manufacturer"
                            value="#{bean.manufacturer}" />
                        <h:outputLabel value="Year" for="year" />
                        <h:inputText id="year" value="#{bean.year}" />
                    </h:panelGrid>
                    <h:commandButton value="Create" type="submit"  action="#{bean.create}" rendered="#{bean.createMode}"/>
                    <h:commandButton value="Save" type="submit" action="#{bean.save}" rendered="#{!bean.createMode}" />
                </h:form>       
        </ui:define>
    </ui:composition>
</h:body>

我添加了一些控制台消息，以验证何时调用Bean中的方法以及何时拥有preRenderView事件，该事件永远不会发生.

I added some Console-Messages to verify when the method in the bean is called and when I have the preRenderView-event it never happens.

任何建议我在这里做错了吗?

Any advice what I am doing wrong here?

推荐答案

<f:metadata>必须放在<ui:composition>的<ui:define>内部.

另请参见 <f:metadata>标记文档(重点是我的):

See also <f:metadata> tag documentation (emphasis mine):

声明此视图的元数据构面.这必须是<f:view>的子级. 此标记必须驻留在给定viewId的顶级XHTML文件中，或者驻留在模板客户端中，但不能驻留在模板中.实现必须确保构面的直接子级是UIPanel，甚至如果该方面只有一个孩子.实现必须将UIPanel的ID设置为UIViewRoot.METADATA_FACET_NAME符号常量的值.

Declare the metadata facet for this view. This must be a child of the <f:view>. This tag must reside within the top level XHTML file for the given viewId, or in a template client, but not in a template. The implementation must insure that the direct child of the facet is a UIPanel, even if there is only one child of the facet. The implementation must set the id of the UIPanel to be the value of the UIViewRoot.METADATA_FACET_NAME symbolic constant.

简单的原因是因为元数据应该是特定于视图的，而不是特定于模板的.

The simple reason is because the metadata is supposed to be view-specific, not template-specific.

更新:事实证明根本没有调用该操作方法.您在命令按钮上有一个rendered属性，该属性似乎根据症状取决于基于请求的变量而不是基于视图的变量.将托管bean放入视图范围应该可以解决此问题.另请参见 commandButton/commandLink/ajax action/listener方法未调用或输入值未更新

Update: it turns out that the action method is not invoked at all. You've there a rendered attribute on the command button which seems according the symptoms to be dependent on a request based variable instead of a view based variable. Putting the managed bean in the view scope should fix this problem. See also commandButton/commandLink/ajax action/listener method not invoked or input value not updated

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