How can I create a DropDownList?

Question

I have two tables: Area and Boss.

An Area has a Boss, it has a foreign key relationship of Area.IDBoss and that is Boss.ID. I hope I'm explaining my question properly. :P

As of now I can manually type in a number in the textbox and it saves correctly, I can also display the name correctly because I'm using Entity Framework, something like "item.Boss.ID" in the View and it works fine.

I really need to display a DropDownList though.

I'm guessing I have to return a collection of available "Boss" rows from my database using the ViewData[] dictionary, but I'm honestly stuck. :D

Any suggestions? This is a very simple use case, so hopefully I don't spend too much time on it. If you guys need any code from my part just say, but I doubt it would help for such a simple question.

As always this site is fantastic, thanks for the help.

Edit: Maybe posting some code would help. Right now I'm receiving this error:

Edit 2: Edited with more recent code that is still not working.

There is no ViewData item of type 'IEnumerable' that has the key 'Jefes'.

And here's the code:

<fieldset>
    <legend>Fields</legend>

    <div class="editor-label">
        <%: Html.LabelFor(model => model.IDJefe) %>
    </div>
    <div class="editor-field">
        <%: Html.DropDownList("Jefes", (SelectList)ViewData["Jefes"]) %>
        <%--<%: Html.TextBoxFor(model => model.IDJefe) %>--%>
        <%: Html.ValidationMessageFor(model => model.IDJefe) %>
    </div>

    <div class="editor-label">
        <%: Html.LabelFor(model => model.Nombre) %>
    </div>
    <div class="editor-field">
        <%: Html.TextBoxFor(model => model.Nombre) %>
        <%: Html.ValidationMessageFor(model => model.Nombre) %>
    </div>

    <p>
        <input type="submit" value="Create" />
    </p>
</fieldset>

JefeRepository jefeRepo = new JefeRepository();
var jefes = jefeRepo.FindAll().OrderBy(x => x.Nombre);
var jefeList = new List<SelectListItem>();
foreach (var jefe in jefes)
{
    jefeList.Add(new SelectListItem()
    {                    
        Text = jefe.Nombre,
        Value = jefe.ID.ToString()
    });
}
ViewData["Jefes"] = jefeList.AsEnumerable();

By the way I translated some variable names from Spanish to English so they would make more sense, sorry for the confusion.

Edit 3: If you guys need any more information please let me know. I've looked over every line of code but it just doesn't work.

Answer 1

You can put an IEnumerable<SelectListItem> in your ViewData[].

var bossDropDown = from boss Area.Boss
                   select new SelectListItem
                   {
                       Value = boss.ID,
                       Text = boss.Name
                   };
ViewData["BossDropDown"] = bossDropDown;

and in your View you can call directly your DropDown like this

<%=Html.DropDownList("BossDropDown", (SelectList)ViewData["BossDropDown"]) %>

EDIT:

With your code, try to change this line

ViewData["jefes"] = jefeList;

to this

ViewData["jefes"] = jefeList.AsEnumerable();

In your view, Change this line

<%: Html.DropDownList("IDJefe", (SelectList)ViewData["jefes"]) %>

to this

<%: Html.DropDownList("jefes", (SelectList)ViewData["jefes"]) %>

since, the name you are calling in your dropdownlist should be the Key of your ViewData that has the IEnumerable<SelectListItem>

Answer 2

do this

JefeRepository jefeRepo = new JefeRepository();
var jefes = jefeRepo.FindAll().OrderBy(x => x.Nombre);
List<SelectListItem> jefeList = new List<SelectListItem>();
foreach (var jefe in jefes)
{
    jefeList.Add(new SelectListItem()
    {                    
        Text = jefe.Nombre,
        Value = jefe.ID.ToString()
    });
}
ViewData["Jefes"] = jefeList;

then

<div class="editor-label">
    <%: Html.LabelFor(model => model.IDJefe) %>
</div>
<div class="editor-field">
    <%: Html.DropDownList("Jefes",ViewData["Jefes"] as List<SelectListItem>, "Select a boss ...") %>
    <%: Html.ValidationMessageFor(model => model.IDJefe) %>
</div>

your mistake: you cant converst a List to a Selectlist, this doesnt work. but honestly, i'd do it like this:

JefeRepository jefeRepo = new JefeRepository();
var jefes = jefeRepo.FindAll().OrderBy(x => x.Nombre);
ViewData["Jefes"] = new SelectList(jefes,"ID", "Nombre");

then

<div class="editor-label">
    <%: Html.LabelFor(model => model.IDJefe) %>
</div>
<div class="editor-field">
    <%: Html.DropDownList("Jefes",ViewData["Jefes"] as SelectList, "Select a boss ...") %>
    <%: Html.ValidationMessageFor(model => model.IDJefe) %>
</div>

let me know which one works best for ya ;)