如何显示多个与asp.net MVC 3和ListBoxFor选择？ [英] How to show multiple selected with asp.net mvc 3 and ListBoxFor?
问题描述
我有这个VM属性。
public IList<Guid> SelectedEligiableCategories { get; set; }
public IList<SelectListItem> EligiableCategories { get; set; }
我有这样的助手在我看来
I have this helpers in my view
@Html.LabelFor(x => x.EligibleCategoryFrmVm.SelectedEligiableCategories, "Eligible Categories:")
@Html.ListBoxFor(x => Model.EligibleCategoryFrmVm.SelectedEligiableCategories, Model.EligibleCategoryFrmVm.EligiableCategories, new { @class = "eligibleCategoryListBox" })
我有这样的code在我的控制器
I have this code in my controller
List<SelectListItem> eligibleCategoriesListItems = Mapper.Map<List<EligibleCategory>, List<SelectListItem>>(eligibleCategories);
foreach (var rewardTier in creditCard.RewardTiers)
{
CbRewardTierFrmVm rewardTierFrmVm = new CbRewardTierFrmVm();
rewardTierFrmVm.EligibleCategoryFrmVm.EligiableCategories = eligibleCategoriesListItems;
foreach (var ec in rewardTier.EligibleCategories)
{
rewardTierFrmVm.EligibleCategoryFrmVm.SelectedEligiableCategories.Add(ec.Id);
}
vm.CbRewardTierFrmVm.Add(rewardTierFrmVm);
}
然而，当我打开了我的观点。我的列表框的值都没有被选中。我不知道为什么。如果这是一个选择列表的这会工作，因为这将在SelectedEligiableCategories匹配到列表中的值
Yet when I load up my view. None of values for my ListBox are selected. I am not sure why. If this was a selectList this would work as it would match up the SelectedEligiableCategories to the value in the list.
我不知道这是否是因为有多个选择
I am not sure if this is because there is multiple selects
修改
<select name="CbRewardTierFrmVm[63b504c0-0f9a-47ba-a8ff-db85f48d5f0f].EligibleCategoryFrmVm.SelectedEligiableCategories" multiple="multiple" id="CbRewardTierFrmVm_63b504c0-0f9a-47ba-a8ff-db85f48d5f0f__EligibleCategoryFrmVm_SelectedEligiableCategories" data-val-required="Must choose at least one eligible category." data-val="true" class="eligibleCategoryListBox ui-wizard-content ui-helper-reset ui-state-default" style="display: none;">
<option value="ed2bb5f9-4565-4f69-ab15-9fca011c0692">Gas</option>
</select>
你觉得这是因为我使用的http://blog.stevensanderson.com/2010/01/28/editing-a-variable-length-list-aspnet-mvc-2-style/ ？
EDIT2
我已先行作出了榜样。我必须失去了一些东西（不知道）。当我使用达林季米特洛夫它的工作原理。
I gone ahead and make an example. I must be missing something(not sure what). When I use "Darin Dimitrov" it works.
我切换到一张下拉，因为我用它得到了同样的问题也是如此。
I switched the example to a dropdown as I am getting the same problem with it as well.
在这个例子中，我没有使用视图模型，因为我最初的假设是不知何故，我是从史蒂芬桑德斯使用助手可能会影响它，所以我打算过他的榜样。
In this example I am not using a viewmodel since my initial assumption was somehow the helper I was using from Steven Sanders might be effecting it so I was going off his example.
这似乎并没有出现这种情况，因为我删除，并仍然得到这个问题。
This does not seem to be the case as I removed it and still get this problem.
public class Gift
{
public string Name { get; set; }
public double Price { get; set; }
public string SelectedItem { get; set; }
public IList<SelectListItem> Items { get; set; }
}
public ActionResult Index()
{
List<SelectListItem> items = new List<SelectListItem>
{
new SelectListItem {Value = "",Text ="--"},
new SelectListItem {Value = "1",Text ="1"},
new SelectListItem {Value = "2",Text ="2"},
};
var initialData = new[] {
new Gift { Name = "Tall Hat", Price = 39.95, Items = items, SelectedItem = "2" },
new Gift { Name = "Long Cloak", Price = 120.00, Items = items, SelectedItem = "1" }
};
return View("Index3",initialData);
}
@model IList<EditorDemo.Models.Gift>
@{
ViewBag.Title = "Index3";
}
@for (int i = 0; i < Model.Count; i++)
{
@Html.DropDownListFor(x => x[i].SelectedItem, new SelectList(Model[i].Items, "Value", "Text"))
}
这似乎并不能够处理，当你把它放在forloop并尝试使多个下拉列表。
It seems to not be able to handle when you put it in forloop and try it make more than one dropdown list.
推荐答案
我下面的作品。
型号：
public class MyViewModel
{
public IList<Guid> SelectedEligiableCategories { get; set; }
public IList<SelectListItem> EligiableCategories { get; set; }
}
控制器：
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel
{
SelectedEligiableCategories = new[]
{
// preselect the second and the fourth item
new Guid("35830042-3556-11E1-BCDC-A6184924019B"),
new Guid("4253876A-3556-11E1-BC17-B7184924019B")
}.ToList(),
EligiableCategories = new[]
{
new SelectListItem { Value = "2DA62E3A-3556-11E1-8A0A-9B184924019B", Text = "item 1" },
new SelectListItem { Value = "35830042-3556-11E1-BCDC-A6184924019B", Text = "item 2" },
new SelectListItem { Value = "3D07EBAC-3556-11E1-8943-B6184924019B", Text = "item 3" },
new SelectListItem { Value = "4253876A-3556-11E1-BC17-B7184924019B", Text = "item 4" },
}
};
return View(model);
}
}
查看：
@model MyViewModel
@using (Html.BeginForm())
{
@Html.ListBoxFor(
x => x.SelectedEligiableCategories,
Model.EligiableCategories,
new { @class = "eligibleCategoryListBox" }
)
}
结果：
更新：
现在，你已经证明为例，允许来说明这个问题，你可以构建时指定所选项目的的SelectList ：
Now that you have shown an example allowing to illustrate the problem, you could specify the selected item when building the SelectList:
@Html.DropDownListFor(
x => x[i].SelectedItem,
new SelectList(Model[i].Items, "Value", "Text", Model[i].SelectedItem)
)
原因值不是preselected是因为你的DropDownList的绑定属性（ X =＆GT; X [I] .SelectedItem ）的列表而在我的例子中，我用一个简单的属性。
The reason a value was not preselected was because you were binding the dropdownlist to a list of properties (x => x[i].SelectedItem) whereas in my example I was using a simple property.
如果你想与你可以使用下面的ListBoxFor帮助做到这一点：
And if you wanted to do this with the ListBoxFor helper you could use the following:
@Html.ListBoxFor(
x => x[i].SelectedItems,
new MultiSelectList(Model[i].Items, "Value", "Text", Model[i].SelectedItems)
)
的 SelectedItems 属性变成采集和我们使用的 MultiSelectList 代替的SelectList 。
The SelectedItems property becomes a collection and we use a MultiSelectList instead of a SelectList.
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