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In May 2006 I wrote two articles that showed how to add a column of checkboxes to a GridView and offer the ability for users to check (or uncheck) all checkboxes in the column with a single click of the mouse. The first article, Checking All CheckBoxes in a GridView, showed how to add "Check All" and "Uncheck All" buttons to the page above the GridView that, when clicked, checked or unchecked all of the checkboxes. The second article, Checking All CheckBoxes in a GridView Using Client-Side Script and a Check All CheckBox, detailed how to add a checkbox to the checkbox column in the grid's header row that would check or uncheck all checkboxes in the column. Both articles showed how to implement such functionality on the client-side, thereby removing the need for a postback.

The JavaScript presented in these two previous articles still works, but the techniques used are a bit antiquated and hamfisted given the advances made in JavaScript programming over the past few years. For instance, the script presented in the previous articles uses server-side code in the GridView's DataBound event handler to assign a client-side onclick event handler to each checkbox. While this works, it violates the tenets of unobtrusive JavaScript, which is a design guideline for JavaScript programming that encourages a clean separation of functionality from presentation. (Ideally, event handlers for HTML elements are defined in script.) Also, the quantity of JavaScript used in the two previous articles is quite hefty compared to the amount of code that would be needed using modern JavaScript libraries like jQuery.

This article presents updated JavaScript for checking (and unchecking) all checkboxes within a GridView. The two examples from the previous articles - checking/unchecking all checkboxes using a button and checking/unchecking all checkboxes using a checkbox in the header row - are reimplemented here using jQuery and unobtrusive JavaScript techniques.

With WebForms, each ASP.NET page's rendered output includes a <form> element that performs a postback to the same page whenever a Button control within the form is clicked, or whenever the user modifies a control whose AutoPostBack property is set to True. This model simplifies web page development, but carries with it some costs - namely, the large amount of data exchanged between the client and the server during a postback. On postback the browser sends the values of all of its form fields (including hidden ones, like view state, which may be quite large) to the server; the server then sends back the entire contents of the web page. While there are some scenarios where this amount of information needs to be exchanged, in many cases the user has performed some action that requires far less information to be exchanged. With a little bit of forethought and code we can have the browser and server exchange much less data, which leads to more responsive web pages and an improved user experience.

Over the past several weeks I've been writing an article series on accessing server-side data from client script. Rather than rely solely on forms and postbacks, many websites use JavaScript code to asynchronously communicate with the server in response to the page loading or some other user action. The server, upon receiving the JavaScript-initiated request, returns just the data needed by the browser, which the browser then seamlessly integrates into the web page. There are a variety of technologies and techniques that can be employed to provide both the needed server- and client-side functionality. Last week's article, Using WCF Services with jQuery and the ASP.NET Ajax Library, explored using the Windows Communication Foundation, or WCF, to serve data from the web server and showed how to consume such a service using both the ASP.NET Ajax Library and jQuery.

In a previous 4Guys article, Creating an Online Boggle Solver, I built an application to find all solutions in a game of Boggle. (Boggle is a word game trademarked by Parker Brothers and Hasbro that involves several players trying to find as many words as they can in a 4x4 grid of letters.) This article takes the lessons learned in Using WCF Services with jQuery and the ASP.NET Ajax Library and uses them to update the user interface for my online Boggle solver, replacing the existing WebForms-based user interface with a more modern and responsive interface. I also used jQuery Templates, a JavaScript-based templating library that is useful for displaying the results from a server-side service.