Populate dropdownlist based on another dropdownlist using AngularJs in MVC

In this article I am going to explain how to populate dropdownlist based on another dropdownlist using AngularJs in MVC

In the previous article I have explained Populate dropdownlist using AngularJs inasp.net MVC, Get data from database and display using AngularJs in asp.net MVC and Create first application with angularJs in asp.net mvc.

Description:

I want to fill state dropdownlist based on Country dropdown selection and city dropdown based on state dropdown selection. For example if I select Country India, all Indian state be shown in state dropdown and similarly select state (Himachal Pradesh) city dropdown will be populate with all himachal’s cities stored in database.

Implementation:

Below given are the classes in Model:-

Country.cs

    public partial class Tb_Country

    {

        public int Id { get; set; }

        public string CountryName { get; set; }

    }

State.cs

    public partial class Tb_State

    {

        public int Id { get; set; }

        public string StateName { get; set; }

        public Nullable<int> CountryId_Fk { get; set; }

    }

City.cs

   public partial class Tb_City

    {

        public int Id { get; set; }

        public string CityName { get; set; }

        public Nullable<int> StateId_Fk { get; set; }

    }

Add controller

Now add a controller to project. Here I have added empty controller. Create Json action to fetch the data from database. Write the code as given below:

Controller Code(IndexController.cs):

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using MVC_Project.Models;

namespace MVC_Project.Controllers

{

    public class IndexController : Controller

    {

        //

        // GET: /Index/

        DemoEntities1 db = new DemoEntities1();

        public ActionResult Index()

        {

            return View();

        }

        public JsonResult GetCountry()

        {

            var country = db.Tb_Country.Select(c=> new{c.Id,c.CountryName}).ToList();

            return Json(country, JsonRequestBehavior.AllowGet);

        }

        [HttpPost]

        public JsonResult Getstate(int CountryId_Fk)

        {

            var state = db.Tb_State.Where(s => s.CountryId_Fk == CountryId_Fk).Select(s => new { s.Id, s.StateName }).OrderBy(s=>s.StateName).ToList();

            return Json(state);

        }

        [HttpPost]

        public JsonResult GetCity(int StateId_Fk)

        {

            var city = db.Tb_City.Where(c => c.StateId_Fk == StateId_Fk).Select(c => new { c.Id, c.CityName }).OrderBy(c=>c.CityName).ToList();

            return Json(city);

        }

    }

}

Add View

Add a view for Index action. Add the reference of AngularJs to view. Below is the code of view.

View (Index.cshtml):

@{

    ViewBag.Title = "Cascading dropdown AngulatJs example";

} 

<fieldset style="width: 25%;">

    <legend>Cascading dropdown AngulatJs example</legend>

    <div ng-app="mvcapp" ng-controller="IndexController">

        <div>

            Select Country :<select ng-model="country" ng-options="c.Id as c.CountryName for c in countries | orderBy:'CountryName'" ng-change="Getstate()">

                <option value="">--Select Country--</option>

            </select> {{country}}

        </div>

        <div style="margin-top: 20px;">

            Select State :<select ng-model="state" ng-options="s.Id as s.StateName for s in states" ng-change="GetCity()" style="margin-left: 20px;">

    <option value="">--Select State--</option>

</select> {{state}}

        </div> 

        <div style="margin-top: 20px;">

            Select City: <select ng-model="city" ng-options="city.Id as city.CityName for city in cities" style="margin-left: 24px;">

    <option value="">--Select City--</option>

</select> {{city}}

        </div>

    </div>

</fieldset>

<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.5.5/angular.js"></script>

<script>

    var angular = angular.module('mvcapp', []);

    angular.controller('IndexController', function ($scope, $http) {

        debugger

        $http({

            method: 'Get',

            url: '/Index/GetCountry'

        }).success(function (data) {

            $scope.countries = data;

        });

        $scope.Getstate = function () {

            debugger

            var CountryId_Fk = $scope.country;          

            if (CountryId_Fk) {

                $http({

                    method: 'POST',

                    url: '/Index/Getstate',

                    data: JSON.stringify({ CountryId_Fk: CountryId_Fk })

                }).success(function (data) {

                    $scope.states = data;

                })

            }          

        }

        $scope.GetCity = function () {

            debugger

            var StateId_Fk = $scope.state;

            if (StateId_Fk) {

                $http({

                    method: 'POST',

                    url: '/Index/GetCity',

                    data: JSON.stringify({ StateId_Fk: StateId_Fk })

                }).success(function (data) {

                    $scope.cities = data;

                })

            }           

        }

    });  

</script>