Retrieving entities as SelectListItems

Question

Hopefully someone can point out what I'm doing wrong here. I'm trying to retrieve several objects from a the DbContext and convert them into SelectListItems as I retrieve them. I've read several posts about this and they seem to be doing the same thing I am, but when I run this code it's always just a SelectList of SelectListItems whose names are "System.Web.MVC.SelectListItem" and Id is null. Here's the code:

        var wtf = db.Departments.ToList().Select(m => new SelectListItem
        {
            Text = m.Name,
            Value = m.Id.ToString()
        });

        SelectList dafuq = new SelectList(wtf);

        ViewBag.Departments = dafuq;

        return View(model);

No exceptions are thrown or anything.

If I just call

var omg = db.Departments.ToList();

before that it returns the objects as expected.

Thanks!

Answer 1

Try this instead:

var wtf = db.Departments.ToList()
var dafuq = new SelectList(wtf, "Id", "Name");
ViewBag.Departments = dafuq;

return View(model);

Answer 2

You don't need to a SelectList. A SelectList created with the 1-parameter constructor converts all of the values in the IEnumerable to strings by calling Convert.ToString() on them, so that's what you're seeing here.

If you have an IEnumerable<SelectListItem> (which is what wtf is), then you can pass that directly to the DropDownList helpers.

Just use your wtf object in your dropdown, and skip the SelectList:

 ViewBag.Departments = wtf;

 @Html.DropdownListFor(m => m.Something, ViewBag.Departments);

And as vorninp pointed out, you don't need to call .ToList() before calling .Select(). In fact, I would recommend against it.

Answer 3

If I'm not mistaken this form of constructor expects just enumerable containing items which then converted internally into selectlistitems.

So you can pass departmens and point the properties of text and data field:

new SelectList(departments,"Id","Name")

Answer 4

Or just-

ViewBag.Departments= db.Departments.ToList();

And In view-

@Html.DropdownListFor(m=>m.Departments,new SelectList(ViewBag.Departments,"ID","DepartmentName"),"Select Dropdown...",htmlAttributes:new{})