SelectOneMenu更新其他SelectOneMenu

Question

我想在选择第一个SelectOnMenu的任何项目时更新第二个SelectOneMenu.就像现在一样,我从ManagedBean获取SelectOneMenus的值.我想我将使用AJAX(jquery)将参数发送到ManagedBean.

<h:form>
    <div class="center">
        <h:panelGrid id="editTable" columns="2" styleClass="center">
            ...
            <h:outputText value="#{msg.timetable_list_category}" />
            <h:selectOneMenu class="category">
                <f:selectItems value="#{categoryBackingBean.categorys}" var="c"
                    itemLabel="#{c.category_Name}" itemValue="#{c.id}" />
            </h:selectOneMenu>

                <h:outputText value="#{msg.timetable_list_seminarblock}" />
            <h:selectOneMenu class="seminarblock">
                <f:selectItems value="#{seminarblockBackingBean.seminarblocks}" var="s"
                    itemLabel="#{s.seminarblock_Name}" itemValue="#{s.seminarblock_Id}" />
            </h:selectOneMenu>
            ...
        </h:panelGrid>
        ...
    </div>
</h:form>

Answer 1

实际上,您可以使用在selectOneMenu的值更改时调用的ValueChangeListener:

<h:selectOneMenu class="category" valueChangeListener="#{yourBean.selectOneMenuListener}">
    <f:selectItems value="#{categoryBackingBean.categorys}" var="c"
        itemLabel="#{c.category_Name}" itemValue="#{c.id}" />
</h:selectOneMenu>

然后,在你的bean中你有这个方法:

public void selectOneMenuListener(ValueChangeEvent event) {
    //This will return you the newly selected
    //value as an object. You'll have to cast it.
    Object newValue = event.getNewValue(); 
    //The rest of your processing logic goes here...
}

要更新页面,您可以添加onchange="submit()"到您的页面<h:selectOneMenu/>.对于某些部分渲染,您可以尝试添加此<f:ajax/>代替onchange="submit()":

<h:selectOneMenu class="category" valueChangeListener="#{yourBean.selectOneMenuListener}">
    <f:selectItems value="#{categoryBackingBean.categorys}" var="c"
        itemLabel="#{c.category_Name}" itemValue="#{c.id}" />
    <f:ajax event="change" execute="@form" render="theIdOfTheComponentYouWantToReRender"/>
</h:selectOneMenu>

如果我没弄错的话,你会想要获得第一个菜单中所选元素的id,并根据它填充第二个元素.然后,您可以渲染另一个selectOneMenu,或者,如果需要,还可以渲染包含表单一部分的面板.