下拉列表MVC#

我想创建一个dropdownlist，但我正在努力解决如何显示它

我有以下代码

控制器

            var trader = new DisplayTradersAttachedToCategoryViewModel
            {
                Description = data.Description,
                Id = data.Id,
                BusinessName = traders.Select(x => new BusinessNameViewModel { BusinessName = x.BusinessName, Id = x.Id }),
                Categories = _service.GetCategories().Select(x => new DropDownViewModel {Id = x.Id, Description = x.Description }).OrderBy(x=>x.Description)
            };

            var trader = new DisplayTradersAttachedToCategoryViewModel
            {
                Description = data.Description,
                Id = data.Id,
                BusinessName = traders.Select(x => new BusinessNameViewModel { BusinessName = x.BusinessName, Id = x.Id }),
                Categories = _service.GetCategories().Select(x => new SelectListItem() {Text = x.Description, Value = x.Id.ToString(), Selected = true})
            };

[HttpPost]
            public ActionResult DeleteCategoryFromTradersAttachNewCategory(DisplayTradersAttachedToCategoryViewModel displayTradersAttachedToCategoryViewModel)
            {
                if (displayTradersAttachedToCategoryViewModel.Button == "Back to List") return RedirectToAction("ViewCategories");

            //Update traders with new category
            //delete category

            //if (_service.DeleteCategory((int)deleteCategoryViewModel.Id))
            //{
            //    return RedirectToAction("ViewCategories");
            //}

            return View("DeleteCategoryAttachedToTraders", displayTradersAttachedToCategoryViewModel);
        }

Categories = _service.GetCategories(id).Select(x => new SelectListItem {Text = x.Description, Value = x.Id.ToString()}) 

DisplayTraderSattachedLocategoryViewModel

public class DisplayTradersAttachedToCategoryViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    [UIHint("DropDownEditorTemplate")]
    public IEnumerable<DropDownViewModel> Categories { get; set; }
}

public class DropDownViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }
}

    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    public IEnumerable<SelectListItem> Categories { get; set; }

    public int Category { get; set; }

    public string Button { get; set; } 

public IEnumerable<SelectListItem> Categories { get; set; }

DropDownEditorTemplate

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Internal.ViewModels.Controller.DropDownViewModel>>" %>
<table class="aligncenter">
  <tr class="tRow left"><%
    if (Model != null)
    {%>
      <td>
        <%=Html.DropDownList("Category", Model.)%> 
      </td><%
    }%>                        
  </tr>
</table>

DisplayTraderSattachedLocategoryViewModel

public class DisplayTradersAttachedToCategoryViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    [UIHint("DropDownEditorTemplate")]
    public IEnumerable<DropDownViewModel> Categories { get; set; }
}

public class DropDownViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }
}

    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    public IEnumerable<SelectListItem> Categories { get; set; }

    public int Category { get; set; }

    public string Button { get; set; } 

public IEnumerable<SelectListItem> Categories { get; set; }

当我通过Submit按钮访问控制器时，DisplayTraderSattachedLocategoryViewModel中没有存储任何内容。我做错了什么

提前感谢您的帮助

克莱尔

试着这样做：

 <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Tameside.Internal.ViewModels.BuyWithConfidence.DropDownViewModel>>" %>
 <select>
     <% foreach(var category in Model.Categories) { %>
         <option value="<%= Html.Encode(category.Id) %>"><%= Html.Encode(category.Name %></option>
     <% } %>
 </select>

---

当然，Id和姓名只是我脑海中的成员。使用类别类中的类别。

您可以尝试将其强制转换为

（IEnumerable）

，即

<%=Html.DropDownList("Category", (IEnumerable<SelectListItem>)Model.Categories)%> 

---

感谢ukaszW.pl/ajay_whiz的帮助：-）最后我混合使用了两种答案：

控制器

            var trader = new DisplayTradersAttachedToCategoryViewModel
            {
                Description = data.Description,
                Id = data.Id,
                BusinessName = traders.Select(x => new BusinessNameViewModel { BusinessName = x.BusinessName, Id = x.Id }),
                Categories = _service.GetCategories().Select(x => new DropDownViewModel {Id = x.Id, Description = x.Description }).OrderBy(x=>x.Description)
            };

            var trader = new DisplayTradersAttachedToCategoryViewModel
            {
                Description = data.Description,
                Id = data.Id,
                BusinessName = traders.Select(x => new BusinessNameViewModel { BusinessName = x.BusinessName, Id = x.Id }),
                Categories = _service.GetCategories().Select(x => new SelectListItem() {Text = x.Description, Value = x.Id.ToString(), Selected = true})
            };

[HttpPost]
            public ActionResult DeleteCategoryFromTradersAttachNewCategory(DisplayTradersAttachedToCategoryViewModel displayTradersAttachedToCategoryViewModel)
            {
                if (displayTradersAttachedToCategoryViewModel.Button == "Back to List") return RedirectToAction("ViewCategories");

            //Update traders with new category
            //delete category

            //if (_service.DeleteCategory((int)deleteCategoryViewModel.Id))
            //{
            //    return RedirectToAction("ViewCategories");
            //}

            return View("DeleteCategoryAttachedToTraders", displayTradersAttachedToCategoryViewModel);
        }

Categories = _service.GetCategories(id).Select(x => new SelectListItem {Text = x.Description, Value = x.Id.ToString()}) 

DisplayTraderSattachedLocategoryViewModel

public class DisplayTradersAttachedToCategoryViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    [UIHint("DropDownEditorTemplate")]
    public IEnumerable<DropDownViewModel> Categories { get; set; }
}

public class DropDownViewModel
{
    public int Id { get; set; }
    public string Description { get; set; }
}

    public int Id { get; set; }
    public string Description { get; set; }

    [UIHint("BusinessNameDisplayTemplate")]
    public IEnumerable<BusinessNameViewModel> BusinessName { get; set; }

    public IEnumerable<SelectListItem> Categories { get; set; }

    public int Category { get; set; }

    public string Button { get; set; } 

public IEnumerable<SelectListItem> Categories { get; set; }

public IEnumerable Categories{get；set；}

DeleteCategoryAttachedToTraders.aspx

using (Html.BeginForm("DeleteCategoryFromTradersAttachNewCategory", "Controller",FormMethod.Post))
    <%=Html.DropDownList("Categories")%>

<%=Html.DropDownList("Category", Model.Categories)%> 

此强制转换将不起作用。。它如何将类别强制转换为SelectListItem？也。。。您将整个对象作为参数提供给DropDownList helper，在我看来，它无法识别它生成的html代码中应该显示的内容和应该是值成员的内容。请试用并查看。。。我也给了它另一个选择。。。你可以用SelectListHello ajay__whiz来编写每一条语句，而不是用SelectListHello ajay___________________________________？目前，该值没有通过视图模型返回。只需将“name”属性添加到select标记中即可。将我的帖子标记为answer仍然是一个好主意。。谢谢你的建议；）