使用上下文菜单

Question

我想使用上下文菜单从 h:panelGrid 中删除行：

<h:form id="components_list">
    <h:panelGrid id="entrance_list" columns="2" style="margin-bottom:10px" cellpadding="5">
        <c:forEach items="#{exit.comp}" var="listItem">
            <p:outputLabel value="#{listItem.name}" />
            <p:selectOneMenu  style="width:125px">
                <f:selectItem itemLabel="Select One" itemValue="" />
                <f:selectItem itemLabel="Xbox One" itemValue="Xbox One" />
                <f:selectItem itemLabel="PS4" itemValue="PS4" />
                <f:selectItem itemLabel="Wii U" itemValue="Wii U" />
            </p:selectOneMenu>
        </c:forEach>
    </h:panelGrid>
    <p:contextMenu id="menuArquivos" for=":components_list:entrance_list">
        <p:menuitem value="Move Up" icon="ui-icon-disk" update=":components_list:entrance_list"/>                        
    </p:contextMenu>
</h:form>

管理bean：

@Named
@ViewScoped
public class Exit implements Serializable
{

    private List<EntranceComponentsObj> comp = new ArrayList<EntranceComponentsObj>();

    public void onSelect(SelectEvent event)
    {
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "Item Selected", event.getObject().toString()));
    }

    public void onUnselect(UnselectEvent event)
    {
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "Item Unselected", event.getObject().toString()));
    }

    public void onReorder()
    {
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "List Reordered", null));
    }

    public void addDelay()
    {
        comp.add(new EntranceComponentsObj("Delay", "Sensor"));
    }

    public void addSensor()
    {
        comp.add(new EntranceComponentsObj("Sensor", "Sensor"));
    }

    public void addInductionLoop()
    {
        comp.add(new EntranceComponentsObj("Induction Loop", "Sensor"));
    }

    public void addDatabaseCheck()
    {
        comp.add(new EntranceComponentsObj("Database Check", "Sensor"));
    }

    public void addWhiteListCheck()
    {
        comp.add(new EntranceComponentsObj("White List Check", "Sensor"));
    }

    public void addBlackListCheck()
    {
        comp.add(new EntranceComponentsObj("Black List Check", "Sensor"));
    }

    public List<EntranceComponentsObj> getComp()
    {
        return comp;
    }

    public void setComp(List<EntranceComponentsObj> comp)
    {
        this.comp = comp;
    }

    public void save()
    {
        addMessage("Success", "Data saved");
    }

    public void update()
    {
        addMessage("Success", "Data updated");
    }

    public void deleteRow()
    {
        comp.remove(new EntranceComponentsObj("Delay", "Sensor"));
    }

    public void addMessage(String summary, String detail)
    {
        FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, summary, detail);
        FacesContext.getCurrentInstance().addMessage(null, message);
    }
}

但是当我调用Context Menu并选择删除时没有任何反应。可能是因为找不到Java对象。实现这个的正确方法是什么？