使用 struts2 dojo 标签填充一个下拉列表以选择其他选项
我有两个下拉菜单。我想在选择第一个下拉列表时填充第二个下拉列表。 我正在使用 struts-dojo-tags 来完成此任务。
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<%@ taglib prefix="sx" uri="/struts-dojo-tags"%>
<html>
<head>
<title>Welcome</title>
<script>
</script>
<sx:head />
</head>
<body>
<h2>Struts 2 + Ajax Example 2!</h2>
<s:form name="f1">
<s:textfield name="proj" label="Project Name" />
<s:url id="url" value="/populateStates.action" />
<s:select id="id1" list="countryList"
listKey="countryId" listValue="countryName" headerKey="0"
headerValue="-Select-" label="Country"/>
<s:select id="id2" list="list2" listKey="stateId"
listValue="stateName" headerKey="0" headerValue="-Select-"
label="State" />
<sx:bind sources="id1" targets="id2" events="onchange"
href="%{#url}" />
</s:form>
<br>
</body>
</html>
我的动作类有两个动作方法。
public String populateCountry() throws Exception{
list1 = new ArrayList<Country>();
list1.add(new Country(1, "Country1"));
list1.add(new Country(2, "Country2"));
list1.add(new Country(3, "Country3"));
return SUCCESS;
}
public String populateStates() throws Exception{
System.out.println("populateStates******************"+id1);
list2 = new ArrayList<State>();
if (id1 != null && !id1.equals(""))
{
if(id1.equals("1"))
{
list2.add(new State(1, "UMB1"));
list2.add(new State(2, "UMB2"));
list2.add(new State(3, "UMB3"));
}
else if(id1.equals("2"))
{
list2.add(new State(4, "UMB4"));
list2.add(new State(5, "UMB5"));
list2.add(new State(6, "UMB6"));
}
else if(id1.equals("3"))
{
list2.add(new State(7, "UMB7"));
list2.add(new State(8, "UMB8"));
list2.add(new State(9, "UMB9"));
}
}
return SUCCESS;
}
当第一次加载 jsp 时（使用填充的 Country 下拉列表），将调用第一个操作方法，当我从 Country 下拉列表中选择一个国家/地区时，将调用第二个操作方法。
问题：States 下拉列表未填充。当我调试代码时，我发现当控制到达 populateStates 时，我的 Action 类的所有变量都被重置（id1、id2、list1、list2、proj）。因此我得到一个空的州下拉列表。请帮我解决这个问题。
I have two dropdowns. I want to populate the second dropdown on selection of first dropdown.
I am using struts-dojo-tags for accomplishing this.
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<%@ taglib prefix="sx" uri="/struts-dojo-tags"%>
<html>
<head>
<title>Welcome</title>
<script>
</script>
<sx:head />
</head>
<body>
<h2>Struts 2 + Ajax Example 2!</h2>
<s:form name="f1">
<s:textfield name="proj" label="Project Name" />
<s:url id="url" value="/populateStates.action" />
<s:select id="id1" list="countryList"
listKey="countryId" listValue="countryName" headerKey="0"
headerValue="-Select-" label="Country"/>
<s:select id="id2" list="list2" listKey="stateId"
listValue="stateName" headerKey="0" headerValue="-Select-"
label="State" />
<sx:bind sources="id1" targets="id2" events="onchange"
href="%{#url}" />
</s:form>
<br>
</body>
</html>
My action class has two action methods.
public String populateCountry() throws Exception{
list1 = new ArrayList<Country>();
list1.add(new Country(1, "Country1"));
list1.add(new Country(2, "Country2"));
list1.add(new Country(3, "Country3"));
return SUCCESS;
}
public String populateStates() throws Exception{
System.out.println("populateStates******************"+id1);
list2 = new ArrayList<State>();
if (id1 != null && !id1.equals(""))
{
if(id1.equals("1"))
{
list2.add(new State(1, "UMB1"));
list2.add(new State(2, "UMB2"));
list2.add(new State(3, "UMB3"));
}
else if(id1.equals("2"))
{
list2.add(new State(4, "UMB4"));
list2.add(new State(5, "UMB5"));
list2.add(new State(6, "UMB6"));
}
else if(id1.equals("3"))
{
list2.add(new State(7, "UMB7"));
list2.add(new State(8, "UMB8"));
list2.add(new State(9, "UMB9"));
}
}
return SUCCESS;
}
First action method is called when the jsp is loaded the first time (with populated Country drop down) and second action method is called when I select a country from the Country dropdown.
Problem: States drop down is not getting populated. When I debug the code, I see that when control reaches populateStates all the variables of my Action class are reset(id1, id2, list1, list2, proj). Due to which I get an empty States dropdown. Please help me to solve this issue.
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评论（1）
我不认为
您可以尝试仅返回
列表（也许这就是您正在做的事情），但我不这样做相信它会起作用。 （如果确实如此，请务必遵循您自己的答案。）我实际上建议使用 jQuery 插件； Dojo 标签已被弃用一段时间，使用非常过时的 Dojo 版本，并且使用起来通常很痛苦。
另一种选择是仅使用普通的旧式 jQuery（或您选择的库）——它几乎总是比通过标签库实现自定义功能更容易。 Ajax 标签库非常适合非常简单的用例，但一旦有任何自定义内容，我不相信它们会节省很多精力。 YMMV。
I don't think
<sx:bind>does what you think it does; the target's HTML will be replaced by what the action returns.You could try returning just the list of
<option>s (and perhaps that's what you're doing), but I don't believe it would work. (If it does, definitely follow up with your own answer.)I'd actually recommend using the jQuery plugin; the Dojo tags have been deprecated for some time, use a very outdated version of Dojo, and often a pain to work with.
Another option would be to just use plain old jQuery (or library of your choice)--it's almost always easier than implementing custom functionality via a tag library. The Ajax tag libraries are great for really simple usecases, but as soon as there's anything custom, I'm not convinced they save much effort. YMMV.