How can I get this ASP.NET MVC SelectList to work?

Question

Hi folks, I create a selectList in my controller, to display in the view.

I'm trying to create it on the fly, sorta thing .. like this...

myViewData.PageOptionsDropDown = 
   new SelectList(new [] {"10", "15", "25", "50", "100", "1000"}, "15");

It compiles, but the output is bad...

<select id="PageOptionsDropDown" name="PageOptionsDropDown">
    <option>10</option>
    <option>15</option>
    <option>25</option>
    <option>50</option>
    <option>100</option>
    <option>1000</option>
</select>

Notice how no item is selected?

How can I fix this??

Update

Just bumping this ... issue still outstanding :(

Answer 1

This is how I do it

IList<Customer> customers = repository.GetAll<Customer>();
IEnumerable<SelectListItem> selectList = 
    from c in customers
    select new SelectListItem
    {
     Selected = (c.CustomerID == invoice.CustomerID),
     Text = c.Name,
     Value = c.CustomerID.ToString()
    };

At second glance I'm not sure I know what you are after...

Answer 2

Using the constructor that accepts items, dataValueField, dataTextField, selectedValue as parameters :

ViewData["myList"] = 
                new SelectList(new[] { "10", "15", "25", "50", "100", "1000" }
                .Select(x => new {value = x, text = x}), 
                "value", "text", "15");

Then in your view :

<%=Html.DropDownList("myList") %>

Answer 3

It may be the case that you have some ambiguity in your ViewData:

Take a look Here

Answer 4

I use an extension method:

usage

var departmentItems = departments.ToSelectList(d => d.Code + 
                                               " - " + d.Description,
                                               d => d.Id.ToString(),
                                               " - ");

var functionItems = customerFunctions.ToSelectList(f => f.Description, 
                                                   f => f.Id.ToString(), 
                                                   " - ");

with

 public static class MCVExtentions
    {
        public static List<SelectListItem> ToSelectList<T>(
            this IEnumerable<T> enumerable, 
            Func<T, string> text, 
            Func<T, string> value, 
            string defaultOption)
        {
            var items = enumerable.Select(f => new SelectListItem()
                                         {
                                             Text = text(f), 
                                             Value = value(f) 
                                         }).ToList();
            items.Insert(0, new SelectListItem()
                        {
                            Text = defaultOption, 
                            Value = "-1" 
                        });
            return items;
        }
    }

Answer 5

This is an option:

myViewData.PageOptionsDropDown = new[] 
{
 new SelectListItem { Text = "10", Value = "10" },
 new SelectListItem { Text = "15", Value = "15", Selected = true }
 new SelectListItem { Text = "25", Value = "25" },
 new SelectListItem { Text = "50", Value = "50" },
 new SelectListItem { Text = "100", Value = "100" },
 new SelectListItem { Text = "1000", Value = "1000" },
}

Answer 6

Using your example this worked for me:

controller:

ViewData["PageOptionsDropDown"] = new SelectList(new[] { "10", "15", "25", "50", "100", "1000" }, "15");

view:

<%= Html.DropDownList("PageOptionsDropDown")%>

Answer 7

I just ran it like this and had no problems,

public class myViewDataObj
    {
        public SelectList PageOptionsDropDown { get; set; }
    }

public ActionResult About()
        {
            myViewDataObj myViewData = new myViewDataObj();
            myViewData.PageOptionsDropDown =
                  new SelectList(new[] { "10", "15", "25", "50", "100", "1000" }, "15");

            ViewData["myList"] = myViewData.PageOptionsDropDown;
            return View();
        }

and

<%=Html.DropDownList("myList") %>

it also worked if you do this,

public ActionResult About()
        {
            myViewDataObj myViewData = new myViewDataObj();
            myViewData.PageOptionsDropDown =
                  new SelectList(new[] { "10", "15", "25", "50", "100", "1000" });

            ViewData["myListValues"] = myViewData.PageOptionsDropDown;
            ViewData["myList"] = "15";
            return View();
        }

and

<%=Html.DropDownList("myList",(IEnumerable<SelectListItem>)ViewData["myListValues"]) %>

Answer 8

It seems if you have a strongly typed view you need to change the ID of the dropdown so that it is NOT the name of a property on the inherrited class. You then need to put some logic in your edit (POST) method to pull off the selected value from the FORMCollection and put it on to your instance before committing your changes.

This is certainly a little strange, but i tried it and it works.

So if you class has a field called CountryId say, and you're displaying a list of country names, make the dropdown have an id of CountryName rather than CountryId, then in the post, you can do something with Collection["CountryName"].

Answer 9

The problem is, SelectList works as designed. The bug is in the design. You may set the Selected Property in SelctedItem, but this will completely be ignored, if you traverse the list with the GetEnumerator() ( or if Mvc does that for you). Mvc will create new SelectfListItems instead.

You have to use the SelectList ctor with the SelectListItem[], the Text-Name, the Value-Name and the SelectedValue. Be aware to pass as SelectedValue the VALUE of SelectListItem, which you want to be selected, not the SelectListItem itself! Example:

SelectList sl = new SelectList( new[]{
  new SelectListItem{ Text="one", Value="1"},
  new SelectListItem{ Text="two", Value="2"},
  new SelectListItem{ Text="three", Value="3"}
}, "Text", "Value", "2" );

(not tested this, but I had the same problem)

then the 2nd option will get the selected="selected" attribute. That looks like good old DataSets ;-)

Answer 10

MonthRepository monthRepository = new MonthRepository();
IQueryable<MonthEntity> entities = monthRepository.GetAllMonth();
List<MonthEntity> monthEntities = new List<MonthEntity>();

foreach(var r in entities)
{
    monthEntities.Add(r);
}

ViewData["Month"] = new SelectList(monthEntities, "MonthID", "Month", "Mars");

Answer 11

Hey folks, the value selected in the model takes advantage instead of the default item. (I agree I didn't read all posts)

Answer 12

This used to work before MVC 2

protected SelectList GetToDoMemberSelectList(int listID, int? sel)
{
    List<ToDoListMember> members =
        Pipe.BServ().GetToDoListMembers().WithListID(listID).ToList();
    SelectList selectList = new SelectList(members, "UserID", "Name", sel);
    return selectList;
}

if sel was null it wouldn't select anything, if not, it would select the relevant value....what has changed?

Answer 13

I can't remember how mvc 1 was setup, but it seems that it wanted the select list named the same as the field it belonged too...

What I found, as someone kind of said above, is that my select lists weren't working in mvc2 when the ViewData they were sent as was named the same as the field.

For example:

<%= Html.DropDownListFor((model => model.ForID), (SelectList)ViewData["ForName"]) %>

works when

<%= Html.DropDownListFor((model => model.ForID), (SelectList)ViewData["ForID"]) %>

does not work as the ViewData name "ForID" is named the same as the field it is working for

Answer 14

So using the example from above:

SelectList sl = new SelectList( new[]{
  new SelectListItem{ Text="one", Value="1"},
  new SelectListItem{ Text="two", Value="2"},
  new SelectListItem{ Text="three", Value="3"}
}, "Text", "Value", "2" );

How do I now ask the sl for the SelectedItem.Text ?

Answer 15

I do it like this:

List<SelectListItem> list = new List<SelectListItem>{
new SelectListItem {Selected = true, Text = "Select", Value = "0"},
new SelectListItem {Selected = true, Text = "1", Value = "1"},
new SelectListItem {Selected = true, Text = "2", Value = "2"}
};
return list.ToArray();

The ToArray() takes care of the problems.