Cascading DropdownList With MVC razor Entity frame work

i have given my code just try it...

in view folder  Index.cshtml

@{
    ViewBag.Title = "DropDownList Demo";
}

<h5>Cascade DropDownList Demo</h5>

@Html.ValidationSummary("Please correct the errors and try again.")

@using (Html.BeginForm())
{
    <fieldset>
        <legend>DropDownList</legend>
        @Html.Label("Name")
        @Html.TextBox("Name")
        @Html.ValidationMessage("Name", "*")

        @Html.Label("State")
        @Html.DropDownList("State", ViewBag.StateName as SelectList, "Select a State", new { id = "State" })
        @Html.ValidationMessage("State", "*")

        @Html.Label("District")
        <select id="District"  name="District"></select>
        @Html.ValidationMessage("District", "*")

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


@Scripts.Render("~/bundles/jquery")
<script type="text/jscript">
    $(function () {
        $('#State').change(function () {
            $.getJSON('/DDL/DistrictList/' + $('#State').val(), function (data) {
                var items = '<option>Select a District</option>';
                $.each(data, function (i, district) {
                    items += "<option value='" + district.Value + "'>" + district.Text + "</option>";
                });
                $('#District').html(items);
            });
        });
    });
</script>




IN Controller DDlController.cs

using MvcCascadingDropdownlist.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MvcCascadingDropdownlist.Controllers
{
    public class DDLController : Controller
    {
        //
        // GET: /DDL/

        public ActionResult Index()
        {
            List<SelectListItem> state = new List<SelectListItem>();
            state.Add(new SelectListItem { Text = "Bihar", Value = "Bihar" });
            state.Add(new SelectListItem { Text = "Jharkhand", Value = "Jharkhand" });
            ViewBag.StateName = new SelectList(state, "Value", "Text");

            return View();
        }

        public JsonResult DistrictList(string Id)
        {
            var district = from s in District.GetDistrict()
                           where s.StateName == Id
                           select s;

            return Json(new SelectList(district.ToArray(), "StateName", "DistrictName"), JsonRequestBehavior.AllowGet);
        }

        [HttpPost]
        public ActionResult Index(ApplicationForm formdata)
        {
            if (formdata.Name == null)
            {
                ModelState.AddModelError("Name", "Name is required field.");
            }
            if (formdata.State == null)
            {
                ModelState.AddModelError("State", "State is required field.");
            }
            if (formdata.District == null)
            {
                ModelState.AddModelError("District", "District is required field.");
            }

            if (!ModelState.IsValid)
            {
                //Populate the list again
                List<SelectListItem> state = new List<SelectListItem>();
                state.Add(new SelectListItem { Text = "Bihar", Value = "Bihar" });
                state.Add(new SelectListItem { Text = "Jharkhand", Value = "Jharkhand" });
                ViewBag.StateName = new SelectList(state, "Value", "Text");

                return View("Index");
            }

            //TODO: Database Insertion
            
            return RedirectToAction("Index", "Home");
        }
    }
}

In Model ApplicationForm.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace MvcCascadingDropdownlist.Models
{
    public class ApplicationForm
    {
        public string Name { get; set; }
        public string State { get; set; }
        public string District { get; set; }
    }

    public class District
    {
        public string StateName { get; set; }
        public string DistrictName { get; set; }

        public static IQueryable<District> GetDistrict()
        {
            return new List<District>
            {
                new District { StateName = "Bihar", DistrictName = "Motihari" },
                new District { StateName = "Bihar", DistrictName = "Muzaffarpur" },
                new District { StateName = "Bihar", DistrictName = "Patna" },
                new District { StateName = "Jharkhand", DistrictName = "Bokaro" },
                new District { StateName = "Jharkhand", DistrictName = "Ranchi" },
            }.AsQueryable();
        }
    }
}