Hi guys today I am going to demonstrate that how we can create cascade dropdown list control in asp.net MVC 5 using Razor and entity framework. Usually we need this solution.

1. Create a new Project. Open Visual Studio 2013.
2. Go to “File” => “New” => “Project…”.
3. Select “Web” in installed templates.
4. Select “ASP.NET MVC Web Application”.
5. Enter the Name and choose the location.
6. Click “OK”.

Create Database Tables (country and state)

Following is the database script of country and state

CREATE TABLE [dbo].[country](

       [country_id] [int] IDENTITY(1,1) NOT NULL,

       [country_name] [varchar](50) NOT NULL,

       [country_abbrev] [varchar](3) NOT NULL,

PRIMARY KEY CLUSTERED

(

       [country_id] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

 

GO

 

SET ANSI_PADDING OFF

GO

CREATE TABLE [dbo].[state](

       [state_id] [int] IDENTITY(1,1) NOT NULL,

       [country_id] [int] NULL,

       [state_name] [varchar](50) NOT NULL,

       [state_abbrev] [varchar](2) NOT NULL,

 CONSTRAINT [PK__state__81A47417FDC731AD] PRIMARY KEY CLUSTERED

(

       [state_id] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

 

GO

 

SET ANSI_PADDING OFF

GO

 

ALTER TABLE [dbo].[state]  WITH CHECK ADD  CONSTRAINT [FK_state_country] FOREIGN KEY([country_id])

REFERENCES [dbo].[country] ([country_id])

GO

 

Step 3: Now open visual studio and add an edmx file (which connect your database).here I am not telling you how to create edmx file , for it you can visit my old blogs based on entity framework.

Step 4: Crate new empty Home Controller.

Step 5. Write following code in Home controller.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using CascadDD.Models;

 

namespace CascadDD.Controllers

{

    public class HomeController : Controller

    {

        //

        // GET: /Home/

 

        TeachersEntities db = new TeachersEntities();

        public ActionResult Index()

        {

            ViewBag.Countries = db.countries.ToList();

            ViewBag.Classes = db.states.ToList();

 

            return View();

        }

        private IList GetState(int Countryid)

        {

            return db.states.Where(m => m.country_id == Countryid).ToList();

        }

        [AcceptVerbs(HttpVerbs.Get)]

        public JsonResult LoadStatesByCountryId(string Countryid)

        {

            var StateList = this.GetState(Convert.ToInt32(Countryid));

            var StatesData = StateList.Select(m => new SelectListItem()

            {

                Text = m.state_name,

                Value = m.state_id.ToString(),

            });

            return Json(StatesData, JsonRequestBehavior.AllowGet);

        }

    }

}

Step 5: Add New Empty Index.cshtml in Index action of Home Controller and write following code into it.

@model CascadDD.Models.TeachersEntities

@{

    ViewBag.Title = "Index";

} 

Index

 

Students

@Html.DropDownListFor(Model => Model.countries, new SelectList(ViewBag.Countries as System.Collections.IEnumerable, “country_id”, “country_name”), “Select a Country”, new { id = “dd_Country” })

 

@Html.DropDownListFor(Model => Model.states, new SelectList(Enumerable.Empty(), “state_id”, “statename”), “Select a State”, new { id = “ddState” })

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