< h：selectOneListbox disabled = true导致NullPointerException [英] <h:selectOneListbox disabled=true causing NullPointerException

问题描述

我有JSF 1.1页面，其中我有一个< h：selectOneListbox 。当我设置属性disabled = true时，中的选定值< h：selectOneListbox 在提交页面时变为空。

I have JSF 1.1 page in which I have a <h:selectOneListbox. When I set property disabled=true, selected value in <h:selectOneListbox becomes null upon submitting the page.

<h:selectOneListbox size="1" id="prod"  disabled="#{mybean.disable}" 

如果将属性设置为disabled = true，我如何确保选中的值不为空。

How can I make sure value selected is not null even if property is set to disabled=true.

谢谢

推荐答案

当在HTML输入元素上设置禁用属性时，那么它不仅是不可编辑的，而且还不将其name = value对作为请求参数发送到服务器。这就解释了为什么服务器为它们检索 null 。

When the disabled attribute is set on a HTML input element, then it is not only uneditable, but it would also not send its name=value pair as request parameter to the server. That explains why the server retrieves nulls for them.

如果你想使它不可编辑，但仍然想要要将其name = value对作为请求参数发送到服务器，那么您应该使用 readonly 而不是。

If you want to make it uneditable, but still want to send its name=value pair as request parameter to the server, then you should be using readonly instead.

<h:someInput ... readonly="true">

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