DropDownList MVC C#

Question

I want to create a dropdownlist, but am struggling with how I display it.

I have the following code.

Controller

            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)
            };

DisplayTradersAttachedToCategoryViewModel

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; }
}

DropDownViewModel

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

I dont know what I'm meant to provide within the DropDownList or if I'm actually doing it correct.

UPDATE

Controller

            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})
            };

DisplayTradersAttachedToCategoryViewModel

    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; }

DeleteCategoryAttachedToTraders.aspx

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

Controller

[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);
        }

When I access the controller via the Submit button nothing is stored within the DisplayTradersAttachedToCategoryViewModel. What am I doing wrong?

Thanks in advance for any help.

Clare

Łukasz W. · Accepted Answer · 2010-07-28 10:47:04Z

2

Try like this:

 <%@ 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>

ofcourse Id and Name are just members out of my head. Use those which are in your category class.

edited Jul 28, 2010 at 10:47

answered Jul 28, 2010 at 10:30

Łukasz W.

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3 Comments

ClareBear Over a year ago

How do I name the select list? At the moment the value is not being returned via the view model.

Łukasz W. Over a year ago

Just put the 'name' attribute to the select tag

Łukasz W. Over a year ago

It's still a good idea to mark my post as answer.. Thanks in advice ;)

ajay_whiz · Accepted Answer · 2010-07-28 10:39:59Z

0

you can try casting it to (IEnumerable<SelectListItem>) i.e.

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

-or-

create a model property of type SelectList and you can initialize it as

new SelectList(Categories.ToList(), "ID", "Description");

answered Jul 28, 2010 at 10:39

ajay_whiz

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3 Comments

Łukasz W. Over a year ago

This cast will not work.. how can it cast Category to SelectListItem? Also... You give a whole object as a parameter to DropDownList helper and in my opinion it cannot recognize what should be display and what should be value member in html code that it generates.

ajay_whiz Over a year ago

try it out and see... also i had given alternate to it... instead of writing for each statement you can do it with SelectList

ClareBear Over a year ago

Hello ajay_whiz, I am trying it your way but can you have a look at my post again as the data isn't getting passed through the viewmodel

ClareBear · Accepted Answer · 2010-07-29 13:33:25Z

0

Thanks ŁukaszW.pl / ajay_whiz for your help :-) In the end I used a mixture of both answers:

Controller

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

DisplayTradersAttachedToCategoryViewModel

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

DeleteCategoryAttachedToTraders.aspx

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

answered Jul 29, 2010 at 13:33

ClareBear

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