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问题:

I have some problem's with a simple application in JSF 2.0.

I try to build a ToDo List with ajax support. I have some todo strings which I display using a datatable. Inside this datatable I have a commandLink to delete a task. The problem is now that the datatable don't get re-rendered.

    <h:dataTable id="todoList" value="#{todoController.todos}" var="todo">         <h:column>                 <h:commandLink value="X" action="#{todoController.removeTodo(todo)}">                     <f:ajax execute="@this" render="todoList" />                 </h:commandLink>         </h:column>         <h:column>             <h:outputText value="#{todo}"/>         </h:column>     </h:dataTable>

Thanks for your help.

Edit (TodoController):

@ManagedBean @SessionScoped public class TodoController {  private String todoStr; private ArrayList<String> todos;  public TodoController() {     todoStr="";     todos = new ArrayList<String>(); }  public void addTodo() {     todos.add(todoStr); }  public void removeTodo(String deleteTodo) {     todos.remove(deleteTodo); }  /* getter / setter */ }

回答1:

(Looks like I don't have enough reputation to comment on others' answers)

I think FRotthowe suggests wrapping the table with another element and referencing it using absolute reference (ie. naming all the parent containers from the root of the document) from the <f:ajax> tag.

Something like this:

<h:form id="form">     <h:panelGroup id ="wrapper">         <h:dataTable value="#{backingBean.data}" var="list">             <h:column>                 <h:commandButton value="-" action="#{backingBean.data}">                     <f:ajax render=":form:wrapper"/>                 </h:commandButton>             </h:column>     </h:dataTable>     </h:panelGroup> </h:form>

But, using absolute references is always a source of problems and increases exponentially the refactoring time as the view grows.

Isn't there a way to just render the table from a <f:ajax> tag (prevent jsf from adding those annoying ":number_of_row" in the ajax event)?

回答2:

I assume that the <h:dataTable> is enclosed by a form?

After struggling with this issue for a while, I googled an easy and clean solution: add @form to render attribute of <f:ajax> and voila!

Full example:

<h:form id="theForm">     <h:dataTable id="table" value="#{tasksMgr.allTasks}" var="task">          <h:column>            #{task.name}         </h:column>          <h:column>             <h:commandButton id="removeTaskButton" value="X" action="#{tasksMgr.removeTask(task)}">                 <f:ajax render="@form" />             </h:commandButton>         </h:column>     </h:dataTable> </h:form>

The full article which helped me is here: http://blogs.steeplesoft.com/2009/10/jsf-2-hdatatable-and-ajax-updates/

回答3:

I ran into the same problem and figured that if you put an element (e.g. ) around the table and rerender that, it will work. I am however not quite sure why it is that way. Anyone?

回答4:

For some reason JSF is modifying the id in the <f:ajax> tag in the button. If I write this xhtml:

<h:form id="form">     <h:commandButton value="Button">         <f:ajax render="table"/>     </h:commandButton>      <h:dataTable id="table" value="#{tableData.data}">         <h:column>             <h:commandButton value="Button">                 <f:ajax render="tocoto"/>             </h:commandButton>         </h:column>     </h:dataTable> </h:form>

I get this html:

<form id="j_idt7" name="j_idt7" method="post" action="/WebApplication1/faces/index.xhtml" enctype="application/x-www-form-urlencoded">     <input type="hidden" name="j_idt7" value="j_idt7" />     <input id="j_idt7:j_idt8" type="submit" name="j_idt7:j_idt8" value="Button" onclick="mojarra.ab(this,event,'action',0,'j_idt7:table');return false" />      <table id="j_idt7:table"><tbody>         <tr>             <td><input id="j_idt7:table:0:j_idt10" type="submit" name="j_idt7:table:0:j_idt10" value="Button" onclick="mojarra.ab(this,event,'action',0,'j_idt7:table:0');return false" /></td>         </tr>     </tbody></table>       <input type="hidden" name="javax.faces.ViewState" id="javax.faces.ViewState" value="-7634557012794378167:1020265910811114103" autocomplete="off" /> </form>

Notice that the id in the second button is 'j_idt7:table:0' while I'm expecting to get 'j_idt7:table' as I do in the first one.

That doesn't solve the problem but may help to find a workaround.

回答5:

use this code:

<h:form id="form"> <h:panelGroup id="panel">     <h:dataTable id="todoList" value="#{todoController.todos}" var="todo">         <h:column>                 <h:commandLink value="X" action="#{todoController.removeTodo(todo)}">                     <f:ajax render=":form:panel" />                 </h:commandLink>         </h:column>         <h:column>             <h:outputText value="#{todo}"/>         </h:column>     </h:dataTable> </h:panelGroup> </h:form>