Beginning jQuery 2 for ASP.NET Developers: Using jQuery 2 with ASP.NET Web Forms and ASP.NET MVC

322 Pages·2013·9.93 MB·English

by  Bipin Joshi (auth.)

BOOKS FOR PROFESSIONALS BY PROFESSIONALS®
Joshi
Beginning jQuery 2
RELATED
for ASP.NET Developers
By combining jQuery with ASP.NET you get the best of both worlds: the client-side interactivity
and responsiveness of JavaScript with the robustness and extensibility of Microsoft’s web stack.
Beginning jQuery 2 for ASP.NET Developers shows you how.
To begin with, you’ll find out how jQuery hooks up with your ASP.NET controls, and simplifies
event handling by keeping it in the browser. Then you’ll learn to handle dynamic content by
interacting with the DOM. Effects and animations are one of the most popular uses of the jQuery
library, so we cover that next—showing you how to get a sleek modern look and feel to your site
using some of the vast library of JavaScript that’s already out there waiting to be used.
Ajax is one of the areas where jQuery really shines, so you’ll find out how to make Ajax calls to
web services and APIs, to get data onto a page without waiting for slow ASP.NET postbacks every
time. And no book on jQuery would be complete without a first look at jQuery Mobile, to get you
started building sites that work on all the major mobile platforms.
What You’ll Learn:
• How to select DOM elements using powerful jQuery selectors
• Use jQuery with ASP.NET server controls, ASP.NET MVC form fields and other DOM elements
• Manipulate and traverse the DOM tree and add jQuery effects to ASP.NET web pages
• Learn to make Ajax calls and pass JSON data to Web Services, Page Methods, WCF services,
controller action methods, HTTP handlers and Web APIs
• Understand code reuse by creating and using jQuery plugins
• Get introduced to jQuery UI and jQuery mobile and use them in ASP.NET Web Forms and MVC
applications
Shelve in ISBN 978-1-4302-6304-3
.NET 54499
User level:
Beginning–Intermediate

SOURCE CODE ONLINE 9 781430 263043
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Contents at a Glance
About the Author ����������������������������������������������������������������������������������������������������������������xv
About the Technical Reviewer ������������������������������������������������������������������������������������������xvii
Acknowledgments �������������������������������������������������������������������������������������������������������������xix
Introduction �����������������������������������������������������������������������������������������������������������������������xxi
■ Chapter 1: The JavaScript You Need to Know �������������������������������������������������������������������1
■ Chapter 2: A First Look at jQuery ������������������������������������������������������������������������������������33
■ Chapter 3: ASP�NET Controls and jQuery Selectors ����������������������������������������������������������63
■ Chapter 4: Event Handling ���������������������������������������������������������������������������������������������103
■ Chapter 5: DOM Manipulation and Dynamic Content �����������������������������������������������������135
■ Chapter 6: Traversal and Other Useful Methods ������������������������������������������������������������157
■ Chapter 7: Effects and Animations ��������������������������������������������������������������������������������179
■ Chapter 8: Ajax Techniques �������������������������������������������������������������������������������������������193
■ Chapter 9: Creating and Using Plugins ��������������������������������������������������������������������������231
■ Chapter 10: jQuery UI and jQuery Mobile ����������������������������������������������������������������������255
■ Chapter 11: Useful jQuery Recipes for ASP�NET Applications ����������������������������������������281
■ Appendix: Learning Resources ��������������������������������������������������������������������������������������301
Index ���������������������������������������������������������������������������������������������������������������������������������303
v
Introduction
Welcome to the exciting world of jQuery! If you’re an ASP.NET developer looking to turbocharge your ASP.NET
applications with jQuery, you picked the right book. Modern web applications leverage browsers’ resources through
client-side scripting. Although JavaScript is a de facto standard as far as client-side scripting is concerned, there are
several libraries built on top of JavaScript that help developers accomplish their job quickly and easily. jQuery is one
of the most popular JavaScript libraries available today. If you want to develop Ajax-driven, dynamic, and
cross-browser web applications using ASP.NET, understanding jQuery is an invaluable skill.
While using jQuery in ASP.NET Web Forms and ASP.NET MVC projects, you need to combine the power of
jQuery with server controls, controllers, services, and APIs. It is crucial to understand how jQuery can be used
effectively in combination with ASP.NET features and technologies.
To that end, this book teaches you how to harness the power of the jQuery library in your ASP.NET Web Forms
and MVC applications. It helps you understand the foundations of jQuery from the perspective of an ASP.NET
developer in a clear, step-by-step way, so that you can quickly ensure you have this invaluable skill under your belt.
Who This Book Is For
This book is for ASP.NET web developers who want to tap the power of jQuery in their existing or new web
applications. This book doesn’t teach you ASP.NET features. I assume that you’re already comfortable working with
ASP.NET and doing web application development in general.
All the code samples discussed in this book use C# as the server-side programming language, so you should
also know C#. Although no prior knowledge of jQuery is expected, I assume that you’re familiar with the basics of
JavaScript.
The examples illustrated throughout the book use SQL Server and Entity Framework. Although you need not
have a detailed understanding of these technologies, you should at least be familiar with them.
The book uses Visual Studio as the development tool. You should know how to work with Visual Studio to
perform basic tasks such as creating projects and debugging code.
Software Required
To work through the examples in this book, you need the following software:
• Visual Studio 2013
• SQL Server 2012
• jQuery, jQuery UI, and jQuery Mobile library files
• Web browsers: Internet Explorer 9+, Firefox, Chrome, Opera, and Safari
Although I used Visual Studio Ultimate 2013 to develop the book’s examples, most of the examples can also be
developed using Visual Studio Express 2013 for Web.
xxi
■ IntroduCtIon
All the data-driven examples were developed using SQL Server 2012 Express Edition. I use the Northwind sample
database in many examples, and I suggest you install it. You can download the Northwind database and its script from
the MSDN downloads web site.
I used jQuery 2.0.3 to write the examples presented in this book. You should consider downloading the latest
versions of jQuery, jQuery UI, and jQuery Mobile from their official web sites.
It’s always a good idea to test the client scripts you write in all the major browsers. So you might consider
installing the latest versions of Internet Explorer, Firefox, Chrome, Opera, and Safari.
How This Book Is Structured
This book is organized into 11 chapters and one appendix. Here’s a quick overview:
• Chapter 1 gives you a quick recap of JavaScript programming. You can brush up on your
JavaScript skills before taking on jQuery.
• Chapter 2 gives you a peek into jQuery. You learn the basics, such as downloading and
installing jQuery on your machine. You also develop a simple application in ASP.NET Web
Forms and MVC.
• Chapter 3 gives you a detailed understanding of jQuery selectors. You learn to match DOM
elements using powerful and flexible selectors. This chapter also details techniques to deal
with server controls while selecting them in the jQuery code.
• Chapter 4 teaches you one of the most commonly used features: event handling. It covers
commonly used events such as window, keyboard, and mouse events. Some advanced concepts
relating to event handling, such as passing custom data to the event handler, are also covered.
• Chapter 5 is about DOM manipulation using jQuery. Topics covered include applying CSS
styles, working with attributes, and manipulating DOM elements.
• Chapter 6 covers DOM navigation and filtering techniques, including tree traversal, iterating,
searching, working with custom data attributes, and more.
• Chapter 7 teaches you how to apply jQuery effects and animations to Web Form controls
and page elements. You learn to apply fancy effects such as fade-in, fade-out, slide-up and
slide-down. You also learn to apply custom animation effects to page elements.
• Chapter 8 covers an important topic: Ajax techniques offered by jQuery. This chapter discusses
how ASMX web services, WCF services, MVC action methods, and the Web API can be called
from the jQuery code. It also discusses the JSON format and its use in Ajax communication.
• Chapter 9 discusses plugins—a technique to extend the jQuery core. You can develop plugins
to enhance and extend the core functionality offered by jQuery. The chapter discusses the
steps involved in building a plugin and gives you some recommendations to be followed
during the process.
• Chapter 10 gives you an overview of jQuery UI and jQuery Mobile. jQuery UI provides various
widgets that you can add to ASP.NET web applications to provide professional user interface
elements such as dialogs, menus, accordions, and sliders. jQuery Mobile helps you develop
web applications targeted at mobile devices.
• Chapter 11 presents a few recipes that you will find useful in real-world applications. The
recipes covered include implementing Ajax-based paging, client-side sorting, file upload,
autocomplete text box, and cascading drop-down lists.
• The Appendix lists some jQuery learning resources.
xxii
■ IntroduCtIon
Downloading the Source Code
The complete source code for the book is available for download at the book’s companion web site. Visit
http://www.apress.com and go to the book’s information page at http://www.apress.com/9781430263043. You can
then download the source code from the Source Code/Downloads section.
Contacting the Author
You can reach me via my web site: http://www.binaryintellect.net. You can also follow me on popular
social-networking web sites such as Facebook and Twitter (visit my web site for details).
xxiii
Chapter 1
The JavaScript You Need to Know
JavaScript is a programming language that adds interactivity and dynamic content to otherwise static HTML pages.
Behind most fancy frills such as mouseover effects, animations, drop-down menus, and form validations, you will
usually find JavaScript being used in some way or another. jQuery is a JavaScript library that simplifies your client-side
programming tasks and uses the same programming constructs as JavaScript for variables, branching, and looping.
While writing jQuery code, you often need to use these JavaScript programming constructs. Therefore, before you
delve into jQuery programming, you must refresh your JavaScript skills. This chapter is intended to give you a quick
overview of commonly used JavaScript features so that you can use the knowledge gained in this chapter in the
remainder of the book. If you are already familiar with JavaScript, you can skip this chapter, or glance over its content
and jump to the next chapter.
Specifically, you will learn how to do the following:
• Understand basic programming constructs used in JavaScript for branching and looping
• Work with JavaScript variables and data types
• Use built-in string, number, and date functions
• Create and use your own functions
■ Note Although this chapter is intended to give you an overview of the JavaScript language, it does not
cover all JavaScript features. For more information on JavaScript programming, see
https://developer.mozilla.org/en-US/docs/Web/JavaScript.
Your First JavaScript Program
In this section, you will develop a simple ASP.NET Web Form that makes use of JavaScript to seek a confirmation
from the end user. Although the application is not very sophisticated, it does throw light on some basics of JavaScript.
Figure 1-1 shows the Web Form you will develop.
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ChApter 1 ■ the JAvASCript You Need to KNow
Figure 1-1. Your first JavaScript program
As shown in Figure 1-1, the Web Form consists of a couple of Label controls, a TextBox, and a Button server
control. Once you enter a name and hit the Submit button, a confirmation dialog is shown that seeks your consent to
submit the form. Depending on your choice, either the form submission is canceled or the form is submitted to the
server. Upon postback, the entered name is displayed in a Label control.
To begin developing this application, create a new ASP.NET Web Application based on the Empty project template using
Visual Studio (see Figure 1-2).
Figure 1-2. Creating a new ASP.NET Empty Web Application using Visual Studio
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ChApter 1 ■ the JAvASCript You Need to KNow
Add a new Web Form to the project and name it FirstJS.aspx. Design the Web Form as shown in Figure 1-1 by
dragging and dropping the respective server controls from the toolbox. The HTML and server control markup of the
Web Form is shown in Listing 1-1.
Listing 1-1. Markup of FirstJS.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="FirstJS.aspx.cs" Inherits="Chapter_01.
FirstJS" %>
...

<body>
<form id="form1" runat="server">
<h1>First JavaScript Program</h1>
<asp:Label ID="Label1" runat="server" Text="Enter your name :"></asp:Label>
<br />
<br />
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<br />
<br />
<asp:Button ID="Button1" runat="server" Text="Submit" OnClick="Button1_Click" />
<br /><br />
<asp:Label ID="Label2" runat="server" Font-Bold="True" ForeColor="Red"></asp:Label>
</form>
</body>
</html>

The markup contains two Label controls: one that acts as the prompt for the name text box, and the other that is
placed below the Submit button. The server-side click event handler of Button1 simply outputs the name entered by
the user in Label2. Listing 1-2 shows this event handler.
Listing 1-2. Submit Button Server-Side Click Event Handler
protected void Button1_Click(object sender, EventArgs e)
{
Label2.Text = "Hello " + TextBox1.Text;
}

So far, the application doesn’t use any JavaScript. In the next step, you add some JavaScript code that is invoked
when the user clicks the Submit button. To do so, modify the markup of the Submit button as shown here:

<asp:Button ID="Button1" runat="server" Text="Submit" OnClientClick="return confirmName();" ... />

You can add the OnClientClick attribute in two ways: you can either switch to the source view of Visual Studio
IDE and key in the markup shown in bold letters, or set the OnClientClick property of Button1 in the Properties
window. The OnClientClick property is used to specify the client-side (JavaScript) code that is to be executed when
the button is clicked. In this case, you set the OnClientClick property to return confirmName(). confirmName() is a
custom JavaScript function that you will write next.
Go into the <head> section of the Web Form and add a <script> block, as shown in Listing 1-3.
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ChApter 1 ■ the JAvASCript You Need to KNow
Listing 1-3. confirmName() Function
<script type="text/javascript">
function confirmName() {
var textbox = document.getElementById("TextBox1");
var flag = window.confirm("You entered : " + textbox.value + "\n\nDo you wish to continue?");
if (flag) {
return true;
}
else {
return false;
}
}
</script>

The <script> block shown in Listing 1-3 contains a custom JavaScript function named confirmName(). The
confirmName() function is intended to seek confirmation from the end user and accordingly cancel or continue with
the form submission. First, it grabs a reference to the text box using the getElementById() method of the document
object. The document object represents the current web page loaded in the browser window. The getElementById()
method accepts an ID of an HTML element and returns a Document Object Model (DOM) object representing the
element. The return object is stored in a JavaScript variable named textbox. Notice the use of the var keyword to
declare a variable.
■ Note the document object Model, or doM, is a tree structure of the entire htML page loaded in the browser
window. each htML element from the page has a corresponding object in the doM tree that can be used to manipulate
the underlying htML element.
The next line declares a JavaScript variable named flag to store the return value of a built-in function:
window.confirm(). The confirm() function belongs to the window object and allows you to display a dialog to the user
with a developer-defined message. The dialog has OK and Cancel buttons. If the user selects OK, confirm() returns
a Boolean value of true; otherwise, it returns false. The window object represents the container of the document being
displayed (the browser window or a tab in which the page is loaded).
In this example, you display the name entered by the user. Notice the use of the escape sequence \n\n in the
message string to add new lines in the message. The value property of the text box DOM element returns the text
entered in the text box. An if-else block checks the flag variable. If flag is true, the if block returns true; otherwise,
the else block returns false. Depending on the value returned by the confirmName() function, the form is submitted
(true) or the form submission is canceled (false).
■ Note Although confirm() is a method of the window object, in most of the browsers you can simply call it as if it
were a stand-alone function. So, window.confirm() and confirm() mean the same thing in your JavaScript code.
Refer to Figure 1-1 again. Can you see the timestamp printed in the footer of the Web Form? That’s the job of
another <script> block that you place just above the </body> (the end body tag). Listing 1-4 shows this <script> block.
4