Using simple Drop Down Lists in ASP.NET MVC

    public class SignUpModel
    {
        [Required]
        [Display(Name="Name")]
        public string Name { get; set; }

        // This property will hold a state, selected by user
        [Required]
        [Display(Name="State")]
        public string State { get; set; }

        // This property will hold all available states for selection
        public IEnumerable<SelectListItem> States { get; set; }
    }

    public class SignUpController : Controller
    {
        //
        // 1. Action method for displaying 'Sign Up' page
        //
        public ActionResult SignUp()
        {
            // Let's get all states that we need for a DropDownList
            var states = GetAllStates();

            var model = new SignUpModel();

            // Create a list of SelectListItems so these can be rendered on the page
            model.States = GetSelectListItems(states);

            return View(model);
        }

        //
        // 2. Action method for handling user-entered data when 'Sign Up' button is pressed.
        //
        [HttpPost]
        public ActionResult SignUp(SignUpModel model)
        {
            // Get all states again
            var states = GetAllStates();

            // Set these states on the model. We need to do this because
            // only the selected value from the DropDownList is posted back, not the whole
            // list of states.
            model.States = GetSelectListItems(states);

            // In case everything is fine - i.e. both "Name" and "State" are entered/selected,
            // redirect user to the "Done" page, and pass the user object along via Session
            if (ModelState.IsValid)
            {
                Session["SignUpModel"] = model;
                return RedirectToAction("Done");
            }

            // Something is not right - so render the registration page again,
            // keeping the data user has entered by supplying the model.
            return View("SignUp", model);
        }

        //
        // 3. Action method for displaying 'Done' page
        //
        public ActionResult Done()
        {
            // Get Sign Up information from the session
            var model = Session["SignUpModel"] as SignUpModel;

            // Display Done.html page that shows Name and selected state.
            return View(model);
        }

        // Just return a list of states - in a real-world application this would call
        // into data access layer to retrieve states from a database.
        private IEnumerable<string> GetAllStates()
        {
            return new List<string>
            {
                "ACT",
                "New South Wales",
                "Northern Territories",
                "Queensland",
                "South Australia",
                "Victoria",
                "Western Australia",
            };
        }

        // This is one of the most important parts in the whole example.
        // This function takes a list of strings and returns a list of SelectListItem objects.
        // These objects are going to be used later in the SignUp.html template to render the
        // DropDownList.
        private IEnumerable<SelectListItem> GetSelectListItems(IEnumerable<string> elements)
        {
            // Create an empty list to hold result of the operation
            var selectList = new List<SelectListItem>();

            // For each string in the 'elements' variable, create a new SelectListItem object
            // that has both its Value and Text properties set to a particular value.
            // This will result in MVC rendering each item as:
            //     <option value="State Name">State Name</option>
            foreach (var element in elements)
            {
                selectList.Add(new SelectListItem
                {
                    Value = element,
                    Text = element
                });
            }

            return selectList;
        }
    }

    model.States = GetSelectListItems(states);

@model Dropdowns.Models.SignUpModel

@{ ViewBag.Title = "Sign up"; }

<div class="row">
    <div class="col-sm-4 col-sm-offset-4">

        <h1>Sign up</h1>

        <div class="panel panel-default">
            <div class="panel-body">
                @using (Html.BeginForm("SignUp", "SignUp", FormMethod.Post, new { role = "form" })) {

                    @* Name textbox *@
                    <div class="form-group">
                        @Html.LabelFor(m => m.Name)
                        @Html.TextBoxFor(m => m.Name, new { @class = "form-control" })
                    </div>

                    @* State selection dropdown *@
                    <div class="form-group">
                        @Html.LabelFor(m => m.State)
                        @Html.DropDownListFor(m => m.State, // 1. Store selected value in Model.State;
                                                            // when page is rendered after postback,
                                                            // take selected value from Model.State.

                                              // 2. Take list of values from Model.States
                                              Model.States, 

                                              // 3. Text for the first 'default' option
                                              "- Please select a state -", 

                                              //4. A class name to assign to <select> tag
                                              new { @class = "form-control" })
                    </div>

                    <button type="submit" class="btn btn-primary">Sign up</button>
                }
            </div>
        </div>
    </div>
</div>

<select class="form-control" id="State" name="State">
    <option value="">- Please select a state -</option>
    <option value="ACT">ACT</option>
    <option value="New South Wales">New South Wales</option>
    <option value="Northern Territories">Northern Territories</option>
    <option value="Queensland">Queensland</option>
    <option value="South Australia">South Australia</option>
    <option value="Victoria">Victoria</option>
    <option value="Western Australia">Western Australia</option>
</select>