What am i doing wrong with asp.net-mvc dropdownlist?

Question

I use a dropdownlist in one of my create.aspx but it some how doesnt seem to work...

public IEnumerable<SelectListItem> FindAllMeasurements()
    {
        var mesurements = from mt in db.MeasurementTypes
                          select new SelectListItem
                          {
                             Value = mt.Id.ToString(),
                             Text= mt.Name
                          };
        return mesurements;
    }

and my controller,

 public ActionResult Create()
    {
      var mesurementTypes = consRepository.FindAllMeasurements().AsEnumerable();
     ViewData["MeasurementType"] = new SelectList(mesurementTypes,"Id","Name");
     return View();
    }

and my create.aspx has this,

<p>
  <label for="MeasurementTypeId">MeasurementType:</label>
    <%= Html.DropDownList("MeasurementType")%>
     <%= Html.ValidationMessage("MeasurementTypeId", "*") %>
   </p>

When i execute this i got these errors,

DataBinding: 'System.Web.Mvc.SelectListItem' does not contain a 
 property with the name 'Id'.

Darin Dimitrov · Accepted Answer · 2010-05-03T06:32:46.787

7

In your controller you are creating a new SelectList from IEnumerable<SelectListItem> which is not correct because you've already specified the Value and Text properties.

You have two options:

public ActionResult Create()
{
    var mesurementTypes = consRepository.FindAllMeasurements();
    ViewData["MeasurementType"] = mesurementTypes;
    return View();
}

or:

public ActionResult Create()
{
    ViewData["MeasurementType"] = new SelectList(db.MeasurementTypes, "Id", "Name");
    return View();
}

There's also a third and preferred way using strongly typed view:

public ActionResult Create()
{
    var measurementTypes = new SelectList(db.MeasurementTypes, "Id", "Name");
    return View(measurementTypes);
}

and in the view:

<%= Html.DropDownList("MeasurementType", Model, "-- Select Value ---") %>

edited May 03 '10 at 06:32

answered May 03 '10 at 06:21

Darin Dimitrov

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@Ya darin that worked... How to add "Select" as 0th index in that list? – ACP May 03 '10 at 06:23
@PieterG How to add "Select" as 0th index in that list? – ACP May 03 '10 at 06:26
@Pandiya, you could use the proper extension method to add an optional label: `<%= Html.DropDownList("MeasurementType", "-- Please Select a Value ---")%>` – Darin Dimitrov May 03 '10 at 06:26
@Darin how to set value "0" to that "Select" – ACP May 03 '10 at 06:28
@when i inspected my select ``... I want to set `0` as value... – ACP May 03 '10 at 06:31
Using standard helpers this is not possible, you will have to insert a dummy element to your list at the beginning. – Darin Dimitrov May 03 '10 at 06:33
@Darin any suggestion how to do that? – ACP May 03 '10 at 06:35

score 1 · Answer 2 · edited May 23 '17 at 10:32

1

As the error message implies, you need an IEnumerable<SelectList>, not an IEnumerable<Materials>.

The constructor for SelectList has an overload that takes an IEnumerable. See .net MVC, SelectLists, and LINQ

edited May 23 '17 at 10:32

Community

1
1

answered May 03 '10 at 05:08

Robert Harvey

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333
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@Pandiya: Well, it's a completely different question now. I see that you found `SelectList`. – Robert Harvey May 03 '10 at 14:11

What am i doing wrong with asp.net-mvc dropdownlist?

2 Answers2