asp.net-mvc 为级联子列表构建一个空的 MVC DropdownListFor
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Build an empty MVC DropdownListFor for a Cascade Sub-List
提问by Patrick
I would like to build an empty Dropdownlistfor to received the results of a previous Dropdownlisfor selection:
我想建立一个空的 Dropdownlistfor 以接收先前 Dropdownlisfor 选择的结果：
The actual view:
实际视图：
<div id="makes">
@Html.DropDownListFor(m => m.Make_Id, Model.MakeList, HeelpResources.DropdownlistMakeFirstRecord)
</div>
<div id="models">
@Html.DropDownListFor(m => m.Model_Id, Model.ModelList, HeelpResources.DropdownlistModelFirstRecord)
</div>
The actual Controller (to work I had to build an empty SelectedList but it seems strange to have to do this):
实际的控制器（为了工作，我必须构建一个空的 SelectedList 但必须这样做似乎很奇怪）：
public virtual ActionResult Create()
{
// Build the Dropdownlist for the Makes
var makesDto = _makeService.ListAllMakes();
var makesViewModel = Mapper.Map<IList<MakeDto>, IList<MakeViewModel>>(makesDto);
// Build the Dropdownlist for the Models
var makeId = -1;
var modelsDto = _modelService.ListModelByMake(makeId);
var modelsViewModel = Mapper.Map<IList<ModelDto>, IList<ModelViewModel>>(modelsDto);
// Build the ViewModel to return to the View
CreateAdViewModel viewModel = new CreateAdViewModel();
viewModel.MakeList = new SelectList(makesViewModel, "ID", "Name");
viewModel.ModelList = new SelectList(modelsViewModel, "ID", "Name");
return View(viewModel);
}
Is there a way to build something like this: @Html.DropDownListFor(m => m.Model_Id, null)
有没有办法构建这样的东西：@Html.DropDownListFor(m => m.Model_Id, null)
And remove the // Build the Dropdownlist for the Models from the controller?
并从控制器中删除 // 为模型构建下拉列表？
Thanks
谢谢
回答by Patrick
Found a solution that I think is the best because it as no service call to build the dropdroplist empty and it's strongly typed:
找到了一个我认为最好的解决方案，因为它没有服务调用来构建空的 dropdroplist 并且它是强类型的：
@Html.DropDownListFor(m => m.Model_Id, Enumerable.Empty<SelectListItem>(), HeelpResources.DropdownlistModelFirstRecord)
回答by Maniyar Bhargav
The following is working:
以下是工作：
@Html.DropDownListFor(m => m.Model_Id, **new SelectList(new List<string>()**));
回答by Chris
Personally I would do this with a bit of jQuery and an additional partial view. Your form could look like this:
就我个人而言，我会使用一些 jQuery 和一个额外的局部视图来做到这一点。您的表单可能如下所示：
<div id="makes">
@Html.DropDownListFor(m => m.Make_Id, Model.MakeList, HeelpResources.DropdownlistMakeFirstRecord)
</div>
<div id="models">
</div>
<script type="text/javascript">
$(function(){
$("#Make_Id").change(function(){
$("#models").load("/Controller_Name/GetModels/" + this.val());
}
});
</script>
and then in your controller:
然后在您的控制器中：
public ActionResult GetModels(int id)
{
ViewBag.DdlModels = new SelectList(rep.GetModelsForCar(id), "Id", "Name");
return PartialView();
}
and then just stick your drop down list in the GetModels partial view
然后将您的下拉列表粘贴在 GetModels 部分视图中
