如何使用selectOneListBox和AJAX动态更改panelGroup

Question

我想根据所选项目更改菜单的外观。

如何使用托管bean获取selectonelistbox的值？

豆源：

public void selectOneMenuListener(ValueChangeEvent event) { 
    Object newValue = (String) event.getNewValue(); 
    selectedMenu = newValue.toString(); 
} 

public String getSelectedMenu() { 
    return selectedMenu; 
} 

public void setSelectedMenu(String selectedMenu) { 
    this.selectedMenu = selectedMenu; 
} 

页：

<h:panelGroup id="panel"> 
    <h:selectOneListbox id="katProduktu" valueChangeListener="#{produkt_KatBean.selectOneMenuListener}"> 
     <f:selectItems value="#{produkt_KatBean.produkt_KatAllList}" 
      var="pk" itemLabel="#{pk.symbol}" itemValue="#{pk.id}"/> 
     <f:ajax render="produktMenu" event="change" execute="@this" /> 
    </h:selectOneListbox> 
</h:panelGroup> 

<h:panelGroup layout="block" id="produktMenu"> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==1}"> 
     Menu 1 
    </h:panelGroup> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==2}"> 
     Menu 2 
    </h:panelGroup> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==3}"> 
     Menu 3 
    </h:panelGroup>  
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==4}"> 
     Manu 4 
    </h:panelGroup> 
</h:panelGroup> 

谢谢！

Answer 1

请勿使用valueChangeListener。这是工作的错误工具。只需将该属性绑定到菜单组件的value属性并让rendered属性在该属性上截取即可。这样你根本不需要听众。您的rendered比较也不适用于字符串。你应该使用== '1'而不是== 1等等，但是这很笨拙，只是让它Long（或Integer）。

<h:panelGroup id="panel"> 
    <h:selectOneListbox id="katProduktu" value="#{produkt_KatBean.selectedMenu}"> 
     <f:selectItems value="#{produkt_KatBean.produkt_KatAllList}" 
      var="pk" itemLabel="#{pk.symbol}" itemValue="#{pk.id}"/> 
     <f:ajax render="produktMenu" /> 
    </h:selectOneListbox> 
</h:panelGroup> 

<h:panelGroup layout="block" id="produktMenu"> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==1}"> 
     Menu 1 
    </h:panelGroup> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==2}"> 
     Menu 2 
    </h:panelGroup> 
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==3}"> 
     Menu 3 
    </h:panelGroup>  
    <h:panelGroup rendered="#{produkt_KatBean.selectedMenu==4}"> 
     Manu 4 
    </h:panelGroup> 
</h:panelGroup> 

只需

private Long selectedMenu; // Or Integer? Should be the same type as #{pk.id}. 

// +getter +setter 

（请注意，我省略<f:ajax>的event和execute属性，因为它们代表已默认值）