验证失败的回发后如何保留f:viewParam值 [英] How to retain f:viewParam values after postback with validation failed

问题描述

我有简单形式的xhtml页面.此页面用于几个数据表.为了指定数据表(依此类推)，我使用GET请求参数. xhtml页面通过

I have xhtml page with simple form. This page is using for several data tables. To specify data table (and so on), I use GET request parameters. xhtml page receive it through

  <f:metadata>
    <f:viewParam id="page" name="page" value="#{itemsBean.page}"/>
  </f:metadata>

并再次通过导航规则，例如

and pass again by the navigation rules like

  <navigation-case>
  <description>
  Global rule for going to the items page from any page  
  </description>
  <from-outcome>items</from-outcome>
  <to-view-id>/items.xhtml</to-view-id>
  <redirect>
    <view-param>
      <name>page</name>
      <value>#{itemsBean.page}</value>
    </view-param>  
  </redirect>  
  </navigation-case>

但是，如果我在xhtml文件中使用这样的输入

But if I use inputs in the xhtml file like this

  <h:inputText id="itemName" value="#{itemsBean.name}" 
    required="true" requiredMessage="Value for this field required!"/>

在尝试接受输入中没有文本的表单后，我无法恢复视图参数. 我试图使用隐藏的输入来传递参数

I cannot restore view param after trying to accepting form with no text in input. I tried to use hidden input for passing parameters

<h:inputHidden id="page" value="#{itemsBean.page}" />

，但似乎之前运行过验证，而itemsBean.page仍然为空. itemsBean是RequestScoped.我做错了什么?我该如何传递参数?

, but seems like validation runs before and itemsBean.page is still empty. itemsBean is RequestScoped. What things I do wrong? How can I pass the param?

感谢您浪费时间.

推荐答案

您需要保持将请求参数传递给后续请求.在普通香草" HTML中，您确实已经为此使用了<input type="hidden">，但是不幸的是，JSF <h:inputHidden>不能那样工作.如果由于另一个输入字段而导致常规验证失败，则与<h:inputHidden>关联的模型值将根本不会更新.

You need to keep passing request parameters to the subsequent request. In "plain vanilla" HTML you'd indeed have used <input type="hidden"> for this, but the JSF <h:inputHidden> unfortunately doesn't work that way. In case of a general validation failure, caused by another input field, the model value associated with <h:inputHidden> won't be updated at all.

您应该在UICommand组件中使用<f:param>来保留后续请求的请求参数.例如

You should be using a <f:param> in the UICommand component instead to retain request parameters for the subsequent request. E.g.

<h:commandButton ...>
    <f:param name="page" value="#{param.page}" />
</h:commandButton>

或者，您可以使用 <o:form> : //omnifaces.org"rel =" nofollow> OmniFaces JSF实用程序库，它基本上扩展了<h:form>并带有附加属性includeViewParams，该属性使您可以保留表单中后续请求的视图参数操作网址.

Alternatively, you can use the <o:form> of the OmniFaces JSF utility library, it basically extends the <h:form> with an additional attribute includeViewParams which enables you to retain the view parameters for the subsequent request in the form action URL.

<o:form includeViewParams="true">
    ...
</o:form>

如果您有多个命令按钮/链接和ajax操作，这样做可能最终会更容易，并且这是万一您希望在非ajax回发期间保留相同URL的唯一方法.

This may end up to be easier if you have multiple command buttons/links and ajax actions, and this would be the only way in case you'd like to retain the same URL during non-ajax postbacks.

这篇关于验证失败的回发后如何保留f:viewParam值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！