我有两个下拉列表。从第一个选择的值加载另一个。当我在控制器中有帮助方法时，该怎么做？
@using (Html.BeginForm())
{
<div>
<table width="100%" cellpadding="0" cellspacing="0">
<tr>
<td><b>Select a District:</b></td>
<td>@Html.DropDownListFor(m => m.DistrictId,ViewData["DMManagers"] as IEnumerable<SelectListItem>,"Select One")</td>
</tr>
<tr>
<td><b>Select a TM:</b></td>
<td>@Html.DropDownListFor(m => m.TMId,ViewData["TMManagers"] as IEnumerable<SelectListItem>,"Select One")</td>
</tr>
</table>
</div>
}
private void LoadDistrictManagers()
{
var _DMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "District Manager"
select new { c.ChannelGroupId,c.Name }).OrderBy(m => m.Name);
ViewData["DMManagers"] = new SelectList(_DMS,"ChannelGroupId","Name");
}
private void LoadTerritoryManagers(int districtId)
{
var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "Territory" && c.ParentChannelGroupId == districtId
select new { c.ChannelGroupId,c.Name }).OrderBy(m => m.Name);
ViewData["TMManagers"] = new SelectList(_TMS,"Name");
}
public ActionResult SummaryReport()
{
DistrictManagerModel model = new DistrictManagerModel();
LoadDistrictManagers();
return View("AreaManager",model);
}
解决方法
使用HTTPAttributes字段给两个下拉列表的唯一ID：
@Html.DropDownListFor(m => m.DistrictId,"Select One",new {@id="ddlDMManagers"})
应将第二个下拉列表初始化为空列表：
@Html.DropDownListFor(m => m.TMId,Enumerable.Empty<SelectListItem>(),new {@id="ddlTMManagers"})
如果您不介意使用jQuery ajax在第一个下拉列表中触发“更改”事件时更新第二个下拉列表：
$(function() {
$('select#ddlDMManagers').change(function() {
var districtId = $(this).val();
$.ajax({
url: 'LoadTerritoryManagers',type: 'POST',data: JSON.stringify({ districtId: districtId }),dataType: 'json',contentType: 'application/json',success: function (data) {
$.each(data,function (key,TMManagers) {
$('select#ddlTMManagers').append('<option value="0">Select One</option>');
// loop through the TM Managers and fill the dropdown
$.each(TMManagers,function(index,manager) {
$('select#ddlTMManagers').append(
'<option value="' + manager.Id + '">'
+ manager.Name +
'</option>');
});
});
}
});
});
});
将此类添加到您的控制器命名空间中：
public class TMManager
{
public int Id {get; set;}
public string Name {get; set;}
}
您将需要更新控制器操作LoadTerritoryManagers()，以响应ajax请求并返回一个{Id，Name}对象的JSON数组。
[HttpPost]
public ActionResult LoadTerritoryManagers(int districtId)
{
var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "Territory" && c.ParentChannelGroupId == districtId
select new TMManager(){ Id = c.ChannelGroupId,Name = c.Name }).OrderBy(m => m.Name);
if (_TMS == null)
return Json(null);
List<TMManager> managers = (List<TMManager>)_TMS.ToList();
return Json(managers);
}
