CRUD Operations Using Web API 2 and KnockOut.JS
In this article, we explore the concept of CRUD operations, using three powerful and popular technologies to build a simple application.
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In this article, I will demonstrate how we can create sample CRUD (Create, Read, Update, Delete) operations using ASP.NET, Web API2, and Knockout.js. I hope you will like this.
Prerequisites
First, you must have Visual Studio 2015 (.NET Framework 4.5.2) and a SQL Server.
In this post, we are going to:
- Create an MVC application.
- Configure an Entity framework ORM to connect to a database.
- Implementing all the HTTP Services needed.
- Call Services using Knockout.js.
SQL Database Part
Here, you will find the scripts to create your database and table.
Create Database
USE [master]
GO
/****** Object: Database [DBCustomer] Script Date: 3/4/2017 3:23:57 PM ******/
CREATE DATABASE [DBCustomer]
CONTAINMENT = NONE
ON PRIMARY
( NAME = N'DBCustomer', FILENAME = N'c:\Program Files (x86)\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\DBCustomer.mdf' , SIZE = 3072KB , MAXSIZE = UNLIMITED, FILEGROWTH = 1024KB )
LOG ON
( NAME = N'DBCustomer_log', FILENAME = N'c:\Program Files (x86)\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\DBCustomer_log.ldf' , SIZE = 1024KB , MAXSIZE = 2048GB , FILEGROWTH = 10%)
GO
ALTER DATABASE [DBCustomer] SET COMPATIBILITY_LEVEL = 110
GO
IF (1 = FULLTEXTSERVICEPROPERTY('IsFullTextInstalled'))
begin
EXEC [DBCustomer].[dbo].[sp_fulltext_database] @action = 'enable'
end
GO
ALTER DATABASE [DBCustomer] SET ANSI_NULL_DEFAULT OFF
GO
ALTER DATABASE [DBCustomer] SET ANSI_NULLS OFF
GO
ALTER DATABASE [DBCustomer] SET ANSI_PADDING OFF
GO
ALTER DATABASE [DBCustomer] SET ANSI_WARNINGS OFF
GO
ALTER DATABASE [DBCustomer] SET ARITHABORT OFF
GO
ALTER DATABASE [DBCustomer] SET AUTO_CLOSE OFF
GO
ALTER DATABASE [DBCustomer] SET AUTO_CREATE_STATISTICS ON
GO
ALTER DATABASE [DBCustomer] SET AUTO_SHRINK OFF
GO
ALTER DATABASE [DBCustomer] SET AUTO_UPDATE_STATISTICS ON
GO
ALTER DATABASE [DBCustomer] SET CURSOR_CLOSE_ON_COMMIT OFF
GO
ALTER DATABASE [DBCustomer] SET CURSOR_DEFAULT GLOBAL
GO
ALTER DATABASE [DBCustomer] SET CONCAT_NULL_YIELDS_NULL OFF
GO
ALTER DATABASE [DBCustomer] SET NUMERIC_ROUNDABORT OFF
GO
ALTER DATABASE [DBCustomer] SET QUOTED_IDENTIFIER OFF
GO
ALTER DATABASE [DBCustomer] SET RECURSIVE_TRIGGERS OFF
GO
ALTER DATABASE [DBCustomer] SET DISABLE_BROKER
GO
ALTER DATABASE [DBCustomer] SET AUTO_UPDATE_STATISTICS_ASYNC OFF
GO
ALTER DATABASE [DBCustomer] SET DATE_CORRELATION_OPTIMIZATION OFF
GO
ALTER DATABASE [DBCustomer] SET TRUSTWORTHY OFF
GO
ALTER DATABASE [DBCustomer] SET ALLOW_SNAPSHOT_ISOLATION OFF
GO
ALTER DATABASE [DBCustomer] SET PARAMETERIZATION SIMPLE
GO
ALTER DATABASE [DBCustomer] SET READ_COMMITTED_SNAPSHOT OFF
GO
ALTER DATABASE [DBCustomer] SET HONOR_BROKER_PRIORITY OFF
GO
ALTER DATABASE [DBCustomer] SET RECOVERY SIMPLE
GO
ALTER DATABASE [DBCustomer] SET MULTI_USER
GO
ALTER DATABASE [DBCustomer] SET PAGE_VERIFY CHECKSUM
GO
ALTER DATABASE [DBCustomer] SET DB_CHAINING OFF
GO
ALTER DATABASE [DBCustomer] SET FILESTREAM( NON_TRANSACTED_ACCESS = OFF )
GO
ALTER DATABASE [DBCustomer] SET TARGET_RECOVERY_TIME = 0 SECONDS
GO
ALTER DATABASE [DBCustomer] SET READ_WRITE
GO
Create Table
USE [DBCustomer]
GO
/****** Object: Table [dbo].[Customer] Script Date: 3/4/2017 3:24:49 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[Customer](
[CustID] [int] IDENTITY(1,1) NOT NULL,
[FirstName] [varchar](50) NULL,
[LastName] [varchar](50) NULL,
[Email] [varchar](50) NULL,
[Country] [varchar](50) NULL,
CONSTRAINT [PK_Customer] PRIMARY KEY CLUSTERED
(
[CustID] 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 Your MVC application
Open Visual Studio and select File >> New Project.
The "New Project" window will pop up. Select ASP.NET Web Application (.NET Framework), name your project, and click OK.
Next, a new window will pop up for selecting the template. We are going choose Web API template and click OK.
After creating our project, we are going to add the ADO.NET Entity Data Model.
Adding ADO.NET Entity Data Model
To add the ADO.NET Entity Framework, right click on the project name, click Add > Add New Item. A dialog box will pop up. Inside this box, select Visual C# Data then ADO.NET Entity Data Model, and enter a name for your Dbcontext model, such as CustomerModel, and finally click Add.
Next, we need to choose model contain for the EF Designer from the database.
As you can see below, we need to select a server name, then, via a drop down list, connect it to a database panel. You should choose your database name. Finally, click OK.
Now, the Entity Data Model Wizard window will pop up for choosing an object which we need to use. In our case, we are going to choose Customers table and click Finish. Finally, we see that the EDMX model generates a Customer class.
Create a Controller
Now, we are going to create a controller. Right click on the controllers folder > Add > Controller> selecting Web API 2 Controller with actions using Entity Framework > click Add.
In the snapshot given below, we are providing three important parameters:
- Model class: Customer represents the entity that should be used for CRUD operations.
- Data context class: used to establish a connection with the database.
- Finally, we need to name our controller (in this case Customers Controller).
As we already know, Web API is a framework that makes it easy to build HTTP services that reach a broad range of clients including browsers and mobile devices.
It has four methods:
- Get is used to select data.
- Post is used to create or insert data.
- Put is used to update data.
- Delete is used to delete data.
CustomersController.cs
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using System.Web.Http.Description;
using CustomerApp;
using CustomerApp.Models;
namespace CustomerApp.Controllers
{
public class CustomersController : ApiController
{
//DbContext
private DBCustomerEntities db = new DBCustomerEntities();
// GET: api/Customers
public IQueryable<Customer> GetCustomers()
{
return db.Customers;
}
// PUT: api/Customers/5
[ResponseType(typeof(void))]
public IHttpActionResult PutCustomer(int id, Customer customer)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != customer.CustID)
{
return BadRequest();
}
db.Entry(customer).State = EntityState.Modified;
try
{
db.SaveChanges();
}
catch (DbUpdateConcurrencyException)
{
if (!CustomerExists(id))
{
return NotFound();
}
else
{
throw;
}
}
return StatusCode(HttpStatusCode.NoContent);
}
// POST: api/Customers
[ResponseType(typeof(Customer))]
public IHttpActionResult PostCustomer(Customer customer)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.Customers.Add(customer);
db.SaveChanges();
return CreatedAtRoute("DefaultApi", new { id = customer.CustID }, customer);
}
// DELETE: api/Customers/5
[ResponseType(typeof(Customer))]
public IHttpActionResult DeleteCustomer(int id)
{
Customer customer = db.Customers.Find(id);
if (customer == null)
{
return NotFound();
}
db.Customers.Remove(customer);
db.SaveChanges();
return Ok(customer);
}
//GetCustomerByCountry: returns list of nb customers by country
[Route("Customers/GetCustomerByCountry")]
public IList<CustomerData> GetCustomerByCountry()
{
List<string> countryList = new List<string>() { "Morocco", "India", "USA", "Spain" };
IEnumerable<Customer> customerList = db.Customers;
List <CustomerData> result = new List<CustomerData>();
foreach (var item in countryList)
{
int nbCustomer = customerList.Where(c => c.Country == item).Count();
result.Add(new CustomerData()
{
CountryName = item,
value = nbCustomer
});
}
if(result != null)
{
return result;
}
return null;
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
private bool CustomerExists(int id)
{
return db.Customers.Count(e => e.CustID == id) > 0;
}
}
}
Calling Services Using Knockout.js
First of all, we need to install Knockout.js. From the solution explorer panel, right click on references > Manage NuGet Packages…
Next, type Knockout.js in search text box, select the first line as below and click Install.
Now, we need to add a new JS file. Right click on scripts folder > Add > JavaScript File.
App.js
Here, we create our view model that contains all the business logic. Then, we bind it with ko.applyBindings(new viewModel()) which enables us to activate Knockout for the current HTML document.
As you can see in the below code, KO provides observables to bind to the model.
- Ko.observable(): used to define model properties which can notify the changes and update the model automatically.
- Ko.observableArray([]): used to bind list of elements.
var ViewModel = function () {
var self = this;
self.CustID = ko.observable();
self.FirstName = ko.observable();
self.LastName = ko.observable();
self.Email = ko.observable();
self.CountryList = ko.observableArray(['Morocco', 'India', 'USA', 'Spain']);
self.Country = ko.observable();
self.customerList = ko.observableArray([]);
var CustomerUri = '/api/Customers/';
function ajaxFunction(uri, method, data) {
//self.errorMessage('');
return $.ajax({
type: method,
url: uri,
dataType: 'json',
contentType: 'application/json',
data: data ? JSON.stringify(data) : null
}).fail(function (jqXHR, textStatus, errorThrown) {
alert('Error : ' + errorThrown);
});
}
// Clear Fields
self.clearFields = function clearFields() {
self.FirstName('');
self.LastName('');
self.Email('');
self.Country('');
}
//Add new Customer
self.addNewCustomer = function addNewCustomer(newCustomer) {
var CustObject = {
CustID: self.CustID(),
FirstName: self.FirstName(),
LastName: self.LastName(),
Email: self.Email(),
Country: self.Country()
};
ajaxFunction(CustomerUri, 'POST', CustObject).done(function () {
self.clearFields();
alert('Customer Added Successfully !');
getCustomerList()
});
}
//Get Customer List
function getCustomerList() {
$("div.loadingZone").show();
ajaxFunction(CustomerUri, 'GET').done(function (data) {
$("div.loadingZone").hide();
self.customerList(data);
});
}
//Get Detail Customer
self.detailCustomer = function (selectedCustomer) {
self.CustID(selectedCustomer.CustID);
self.FirstName(selectedCustomer.FirstName);
self.LastName(selectedCustomer.LastName);
self.Email(selectedCustomer.Email);
self.Country(selectedCustomer.Country);
$('#Save').hide();
$('#Clear').hide();
$('#Update').show();
$('#Cancel').show();
};
self.cancel = function () {
self.clearFields();
$('#Save').show();
$('#Clear').show();
$('#Update').hide();
$('#Cancel').hide();
}
//Update Customer
self.updateCustomer = function () {
var CustObject = {
CustID: self.CustID(),
FirstName: self.FirstName(),
LastName: self.LastName(),
Email: self.Email(),
Country: self.Country()
};
ajaxFunction(CustomerUri + self.CustID(), 'PUT', CustObject).done(function () {
alert('Customer Updated Successfully !');
getCustomerList();
self.cancel();
});
}
//Delete Customer
self.deleteCustomer = function (customer) {
ajaxFunction(CustomerUri + customer.CustID, 'DELETE').done(function () {
alert('Customer Deleted Successfully');
getCustomerList();
})
}
//Chart Line function used to display a chart which represents nb of customers by country
function chartLine() {
ajaxFunction('http://localhost:50706/Customers/GetCustomerByCountry', 'GET').done(function (result) {
console.log(result);
Morris.Line({
element: 'line-chart',
data: result,
xkey: 'CountryName',
// A list of names of data record attributes that contain y-values.
ykeys: ['value'],
// Labels for the ykeys -- will be displayed when you hover over the
// chart.
labels: ['Value'],
parseTime: false
});
});
};
chartLine();
getCustomerList();
};
ko.applyBindings(new ViewModel());
Now, from the solution explorer panel, we are going to add an index.html file as shown below.
Index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>.: Customer App :. Web API2 Á KnockOutJS</title>
<meta charset="utf-8" />
<!-- CSS -->
<link href="Content/bootstrap.min.css" rel="stylesheet" />
<link href="https://cdn.oesmith.co.uk/morris-0.5.1.css" rel="stylesheet" />
</head>
<body>
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">WEB API2 - KnockOutJS</a>
</div> <!-- END HEADER NAV -->
</div> <!-- END CONTAINER -->
</nav><!-- END NAV-->
<div class="container" style="margin-top: 7%;">
<div class="row">
<div class="col-md-4">
<!-- FORM -->
<div class="panel panel-default">
<div class="panel-heading"> <span class="glyphicon glyphicon glyphicon-tag" aria-hidden="true"></span> <b>Add New Customer</b></div>
<div class="panel-body">
<form>
<div class="form-group" style="display:none;">
<label for="CustomerID">Customer ID</label>
<input type="text" id="CustomerID" class="form-control" data-bind="value:CustID" placeholder="Customer ID" />
</div><!-- END CUSTOMER ID -->
<div class="form-group">
<label for="FirstName">First Name</label>
<input type="text" id="FirstName" class="form-control" data-bind="value:FirstName" placeholder="First Name" />
</div><!-- END FIRST NAME -->
<div class="form-group">
<label for="LastName">Last Name</label>
<input type="text" id="LastName" class="form-control" data-bind="value: LastName" placeholder="Last Name" />
</div><!-- END LAST NAME -->
<div class="form-group">
<label for="Email">Email</label>
<input type="email" id="Email" class="form-control" data-bind="value: Email" placeholder="Email" />
</div> <!-- END EMAIL -->
<div class="form-group">
<label for="Country">Country</label>
<select class="form-control" data-bind="options: CountryList, value: Country, optionsCaption: 'Select your Country ...' " ></select>
</div> <!-- END COUNTRY -->
<button type="button" class="btn btn-success" data-bind="click: addNewCustomer" id="Save">
<span class="glyphicon glyphicon glyphicon-floppy-disk" aria-hidden="true"></span> Save
</button>
<button type="button" class="btn btn-info" data-bind="click: clearFields" id="Clear">
<span class="glyphicon glyphicon glyphicon-refresh" aria-hidden="true"></span> Clear
</button>
<button type="button" class="btn btn-warning" data-bind="click:updateCustomer " style="display:none;" id="Update">
<span class="glyphicon glyphicon glyphicon-pencil" aria-hidden="true"></span> Update Customer
</button>
<button type="button" class="btn btn-default" data-bind="click:cancel " style="display:none;" id="Cancel">
<span class="glyphicon glyphicon glyphicon-remove" aria-hidden="true"></span> Cancel
</button>
</form> <!-- END FORM -->
</div> <!-- END PANEL BODY-->
</div><!-- END PANEL-->
</div> <!-- END col-md-4 -->
<div class="col-md-8">
<div class="panel panel-default">
<div class="panel-heading"><span class="glyphicon glyphicon glyphicon-stats" aria-hidden="true"></span><b> Charting Customer</b> </div>
<div class="panel-body">
<!-- <img src="images/Chart.png" style="width:60%; margin:6px 70px;" /> -->
<div id="line-chart" style="height: 300px;"></div><br/><br/>
</div> <!-- END PANEL-BODY-->
</div> <!-- END PANEL-->
</div> <!-- END col-md-8-->
</div>
<div class="row">
<div class="col-md-12">
<div class="panel panel-default">
<div class="panel-heading">
<span class="glyphicon glyphicon glyphicon-zoom-in" aria-hidden="true"></span> <b>Customer List </b>
<div class="loadingZone" style="color: #000; display:block; float:right; display:none;"> <img src="images/ajax-loader.gif" /> Refresh Data ...</div>
</div>
<div class="panel-body">
<table class="table table-hover">
<thead>
<tr>
<th><span class="glyphicon glyphicon glyphicon-eye-open" aria-hidden="true"></span></th>
<th>#</th>
<th>First Name</th>
<th>Last Name</th>
<th>Email</th>
<th>Country</th>
<th></th>
</tr>
</thead> <!-- END THEAD -->
<tbody data-bind="foreach: customerList">
<tr>
<td> <button type="button" class="btn btn-default btn-xs" data-bind="click: $root.detailCustomer"> <span class="glyphicon glyphicon glyphicon-eye-open" aria-hidden="true"></span></button> </td>
<td> <span data-bind="text: CustID"></span> </td>
<td> <span data-bind="text: FirstName"></span></td>
<td> <span data-bind="text: LastName"></span></td>
<td> <span data-bind="text: Email"></span> </td>
<td> <span data-bind="text: Country"></span> </td>
<td>
<button type="button" class="btn btn-danger btn-xs">
<span class="glyphicon glyphicon glyphicon-trash" aria-hidden="true" data-bind="click: $root.deleteCustomer"></span>
</button>
</td>
</tr>
</tbody> <!-- END TBODY -->
</table> <!-- END TABLE -->
</div>
</div>
</div>
</div>
</div> <!-- END CONTAINER-->
<!-- JS -->
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="Scripts/jquery-1.10.2.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="Scripts/bootstrap.min.js"></script>
<script src="Scripts/knockout-3.4.0.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/raphael/2.1.0/raphael-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/morris.js/0.5.1/morris.min.js"></script>
<!-- app.js-->
<script src="Scripts/app.js"></script>
</body>
</html>
In order to exchange data between an HTML page and JavaScript file, Knockout.js offers various types of binding that should be used within the data-bind attribute.
- Click: represents a click event handler to call a JavaScript function.
- Value: represents the value binding with UI elements to the property defined into view Model.
- Text: represents the text value to the UI element.
- Foreach: used to fetch an array.
Now you can run your application. Don’t forget to change the URL address as below.
http://localhost:55192/index.html
Let’s see the output
That’s all! Please send your feedback and queries via the comments section.
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