JSF-将参数传递给valuechangelistener [英] JSF- passing a parameter to valuechangelistener

问题描述

我有一个像这样的单选按钮:

I have a litte radiobutton like this :

<h:selectOneRadio value="#{test.answer}" valueChangeListener="#{TestService.changeanswer}" immediate="true" id="answer">
 <f:selectItem  itemValue="A" itemLabel="Absolutely True"/>
 <f:selectItem  itemValue="B" itemLabel="True"/>
 <f:selectItem  itemValue="C" itemLabel="Partially True"/>
 <f:selectItem  itemValue="D" itemLabel="Not True"/>
 <f:selectItem  itemValue="E" itemLabel="Definitely Not True"/>
 <f:ajax event="change" process="answer"></f:ajax></h:selectOneRadio>

我的听众就是这样:

public void changeanswer(ValueChangeEvent vcEvent) { 
System.out.println("comeon= " + vcEvent.getOldValue()); 
System.out.println("comeon= " + vcEvent.getNewValue());}

我想将参数传递给changeanswer方法.例如，我想将questionid传递给changeanswer函数.我需要做一些安排.

I would like to pass a parameter to the changeanswer method.For example I want to pass the questionid to the changeanswer function. I need to make some arrangements in it.

我该怎么做?

非常感谢.

布拉德-新秀..

推荐答案

看到组件值是如何绑定的，我敢打赌它在数据表中.如果确实如此，则可以使用 获取当前行.将DataModel属性添加到TestService bean中，如下所示:

Seeing how the component values are bound, I bet that it's inside a datatable. If that is indeed the case, you can use DataModel#getRowData() to obtain the current row. Add a DataModel property to the TestService bean like follows:

private List<Question> questions;
private DataModel<Question> questionModel;

@PostConstruct
public void init() {
    questions = getItSomehow();
    questionModel = new ListDataModel<Question>(questions);
}

public void change(ValueChangeEvent event) {
    Question currentQuestion = questionModel.getRowData();
    // ...
}

，然后按如下所示更改视图:

and change the view as follows:

<h:dataTable value="#{TestService.questionModel}" var="test">

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也就是说，我建议使用比TestService，test和change()更合理的变量名，分别类似于Questionaire，question和changeAnswer().这使代码更具自记录性.

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That said, I'd suggest to use more sensible variable names than TestService, test and change(), like Questionaire, question and changeAnswer() respectively. This makes the code more self-documenting.

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