How to implement cascading dropdownlist in asp.net mvc using angularJS


 

Here we will learn how to implement cascading dropdown list using angularjs and asp.net mvc.

Should have knowledge on:

You should have knowledge on html , javascript , angularJS and C#.net and asp.net MVC

Preparation:

1. In this article we will use asp.net mvc as service provider and angularJS as client side framework.

2. In asp.net mvc we will build 3 services to get Company Locations, Departments and Managers data.

3. We will use AngularJS $http service to get data from these services.

4. We will use scope object to bind data to UI

Execution:

Open visual Studio and select new project from file menu

and select Asp.Net web application template and enter name then click on OK button.

image

Click on empty tile and select MVC checkbox to create Asp.net MVC empty project then click on OK button

image

Add Content folder and bootstrap.min.css file in it, as shown in below screenshot

Add Scripts folder and angular.min.js file in it, as shown in below screenshot

image

Add app.js file in Scripts folder and write the following code in it.

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

 

above code creates angularjs module.

image

Next Create angular Controller for this module as follows

MyModule.controller('myController', ['$scope', '$http', function (scope, http) {
    //Get Locations
    scope.getLocations = function () {
        //Get Locations service call
        http({
            method: 'Get',
            url: '/Home/GetCompanyLocations'
        }).success(function (data, status, headers, config) {
            //assign locations data to scope
            scope.locations = data;
            //setting default value
            if (scope.locations.length > 0) {
                scope.selectedLocation = scope.locations[0];
            }
        }).error(function (data, status, headers, config) {
            alert("Error occured");
        });
    };
    //Get Departments   
    scope.getDepartments = function () {
        if (scope.selectedLocation.Id > 0) {
            scope.departments = null;
            scope.managers = null;
            //Get Departments service call
            http({
                method: 'POST',
                url: '/Home/GetDepartments',
                data: { locationId: scope.selectedLocation.Id }
            }).success(function (data, status, headers, config) {
                //assign departments data to scope
                scope.departments = data;
                //setting default value
                if (scope.departments.length > 0) {
                    scope.selectedDepartment = scope.departments[0];
                }
            }).error(function (data, status, headers, config) {
                alert("Error occured");
            });
        }
        else {
            scope.departments = null;
            scope.managers = null;
        }
    };
    //Get Managers
    scope.getManagers = function () {
        if (scope.selectedDepartment.Id > 0) {
            //Get Managers service call
            http({
                method: 'POST',
                url: '/Home/GetManagers',
                data: { deptId: scope.selectedDepartment.Id }
            }).success(function (data, status, headers, config) {
                //assign managers data to scope
                scope.managers = data;
                //setting default value
                if (scope.managers.length > 0) {
                    scope.selectedManager = scope.managers[0];
                }
            }).error(function (data, status, headers, config) {
                alert("Error occured");
            });
        }
        else {
            scope.managers = null;
        }
    };
}]);

 

Explanation:

In the above code we have 3 service calls for three dropdowns

1. getLocations

This service get called when the page loads, we can use ngInit directive to call some method on load.

In this service call we will get all the company locations and in success call back, we are assigning the locations to scope.locations object and setting default value for the dropdown using selectedLocation model

2. getDepartments

This service get called when the locations dropdown selection changed, we can use ngChnage directive to call some method on change.

In this service call we will get all the location departments and in success call back, we are assigning the departments to scope.departments object and setting default value for the dropdown using selectedDepartment model

2. getManagers

This service get called when the departments dropdown selection changed, we can use ngChnage directive to call some method on change.

In this service call we will get all the department managers and in success call back, we are assigning the managers to scope.managers object and setting default value for the dropdown using selectedManager model

Add Home controller to controllers folder and one model to models folder and add one action method in home controller and generate a view for it.

image

Write models code in Model (CompanyLocation.cs)

namespace CascadingDropdownList.Models
{
    public class CompanyLocation
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
    public class Department
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int LocationId { get; set; }
    }
    public class Manager
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int DepartmentId { get; set; }
    }
}

 

Write 3 services 1. GetCompanyLocations 2. GetDepartments 3. GetManagers as follows

        public JsonResult GetCompanyLocations()
        {
            var locations = new List<CompanyLocation>() {
                new CompanyLocation() { Id=0,Name="–select–"},
                new CompanyLocation() { Id=1,Name="Hyderabad"},
                new CompanyLocation() { Id=2,Name="Chennai"},
                new CompanyLocation() { Id=3,Name="Delhi"},
                new CompanyLocation() { Id=4,Name="Bangalore"}
            };
            return Json(locations, JsonRequestBehavior.AllowGet);
        }
        [HttpPost]
        public JsonResult GetDepartments(int locationId)
        {
            var departments = new List<Department>() {
                new Department() { Id=1,Name="Accounts",LocationId=1},
                new Department() { Id=2,Name="Software",LocationId=1},
                new Department() { Id=3,Name="CustomerCare",LocationId=1},
                new Department() { Id=4,Name="IT",LocationId=1},
                new Department() { Id=5,Name="Software",LocationId=2},
                new Department() { Id=6,Name="CustomerCare",LocationId=2},
                new Department() { Id=7,Name="IT",LocationId=2},
                new Department() { Id=8,Name="Accounts",LocationId=3},
                new Department() { Id=9,Name="CustomerCare",LocationId=3},
                new Department() { Id=10,Name="IT",LocationId=4}
            };
            var result = departments.Where(d => d.LocationId == locationId).ToList();
            result.Insert(0, new Department() { Id = 0, Name = "–select–" });
            return Json(result, JsonRequestBehavior.AllowGet);
        }
        [HttpPost]
        public JsonResult GetManagers(int deptId)
        {
            var locations = new List<Manager>() {
                new Manager() { Id=1,Name="Venki",DepartmentId=1},
                new Manager() { Id=2,Name="Sri",DepartmentId=5},
                new Manager() { Id=3,Name="Balu",DepartmentId=6},
                new Manager() { Id=4,Name="Gopi",DepartmentId=10},
                new Manager() { Id=5,Name="Ramesh",DepartmentId=3},
                new Manager() { Id=6,Name="Ganesh",DepartmentId=2},
                new Manager() { Id=7,Name="Shiva",DepartmentId=7},
                new Manager() { Id=8,Name="Naidu",DepartmentId=2},
                new Manager() { Id=9,Name="ThataRao",DepartmentId=3},
                new Manager() { Id=10,Name="Bala",DepartmentId=4},
                new Manager() { Id=11,Name="Chandu",DepartmentId=8},
                new Manager() { Id=12,Name="Chaitanya",DepartmentId=9}
            };
            var result = locations.Where(d => d.DepartmentId == deptId).ToList();
            result.Insert(0, new Manager() { Id = 0, Name = "–select–" });
            return Json(result, JsonRequestBehavior.AllowGet);
        }

 

Then write following code in View(Index.cshtml)

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>
<link href="~/Content/bootstrap.min.css" rel="stylesheet" />
<script src="~/Scripts/angular.min.js"></script>
<script src="~/Scripts/app.js"></script>
<div ng-app="MyModule">
    @* using ng-init getLocations() method invoked when the div loads*@
    <div ng-controller="myController" ng-init="getLocations()">
        <div class="row">
            <div class="form-group col-md-offset-2 col-md-2">
                <label for="loc">Select Location:</label>
                <select ng-model="selectedLocation" ng-change="getDepartments()" class="form-control" id="loc"
                        ng-options="location.Name for location in locations track by location.Id"></select>
                <br />
                <label for="dept" ng-show="departments">Select Department:</label>
                <select ng-model="selectedDepartment" ng-change="getManagers()" ng-show="departments" class="form-control" id="dept"
                        ng-options="department.Name for department in departments track by department.Id"></select>
                <br />
                <label for="mng" ng-show="managers">Select Manager:</label>
                <select ng-model="selectedManager" ng-show="managers" class="form-control" id="mng"
                        ng-options="manager.Name for manager in managers track by manager.Id"></select>
                <br />
            </div>
        </div>
    </div>
</div>

Output:

image

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image

image

Happy Coding ComputerSmile

Screenshot_18

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