How to set hidden field value in form?

Question

I've encountered a problem while developing a forum using JSF. See this code:
<h:form id="commmentForm" formName="commentForm" >
     <h:input_hidden id="pageId" valueRef="CommentBean.pageId" value="${article.id}"/>
     <h:input_text id="userName" valueRef="CommentBean.userName"/>
     <h:input_text id="userEmail" valueRef="CommentBean.userEmail"/>
     <h:input_text id="userURL" valueRef="CommentBean.userURL"/>
     <h:input_textarea id="content" valueRef="CommentBean.content"/>
     <h:command_button id="submit" label="Leave A Comment" commandName="submit" actionRef="CommentBean.createAction" />
</h:form>
I was trying to specify a hidden field that represents the unique ID number of the current article using <h:input_hidden> tag above. But RI complains that runtime expression is not permitted in 'value' attribute. So I set the attribute 'value' to arbitrary number such as '2', but it seems that CommentBean.pageId is still null.
So the question is:
1. Why can't I use EL in JSF tags attributes?
2. How can I resolve my problem mentioned above?
Thanks very much in advance!

Answer 1

To solve the problem, you have to use two hiddenfields, say:
<h:input_hidden id="pageId"valueRef="CommentBean.pageId" />
<h:input_hidden id="articleId" valueRef="article.id"/>
I want to set the value of CommentBean.pageId to
${article.id} (article is not a managed bean) and to
let CommentBean.createAction insert a database row
whose page_id column is ${article.id}, so I think the
tags you suggested won't work for me.Why can't you interrogate your ComponentBean for its pageId property during your invoke() method? By the time your invoke() method is called, the value from the hidden field will have been pushed to the model, so this should be no problem. You could do Application.getValueBinding("ComponentBean.pageId").getValue() to do so.
Ed