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INTRODUCTION

SIMPLY PUT, ASP.NET 4 IS AN AMAZING TECHNOLOGY to use to build your Web solutions! When

ASP.NET 1.0 was introduced in 2000, many considered it a revolutionary leap forward in the area of Web application development. ASP.NET 2.0 was just as exciting and revolutionary, and ASP.NET 4 is continuing a forward march in providing the best framework today in building applications forthe Web. ASP.NET 4 continues to build on the foundation laid by the release of ASP.NET 1.0/2.0/3.5 by focusing on the area of developer productivity.

This book covers the whole of ASP.NET. It not only introduces new topics, but it also shows you examples of these new technologies in action. So sit back, pull up that keyboard, and enjoy!

A LITTLE BIT OF HISTORY
Before organizations were eventhinking about developing applications for the Internet, much of the application development focused on thick desktop applications. These thick-client applications were used for everything from home computing and gaming to office productivity and more. No end was in sight for the popularity of this application model. During that time, Microsoft developers developed thick-client applications usingmainly Visual Basic (VB). Visual Basic was not only a programming language — it was tied to an IDE that allowed for easy thick-client application development. In the Visual Basic model, developers could drop controls onto a form, set properties for these controls, and provide code behind them to manipulate the events of the control. For example, when an end user clicked a button on one of theVisual Basic forms, the code behind the form handled the event. Then, in the mid-1990s, the Internet arrived on the scene. Microsoft was unable to move the Visual Basic model to the development of Internet-based applications. The Internet definitely had a lot of power, and right away, the problems facing the thick-client application model were revealed. Internet-based applications created a singleinstance of the application that everyone could access. Having one instance of an application meant that when the application was upgraded or patched, the changes made to this single instance were immediately available to each and every user visiting the application through a browser. To participate in the Web application world, Microsoft developed Active Server Pages (ASP). ASP was a quick and easyway to develop Web pages. ASP pages consisted of a single page that contained a mix of markup and languages. The power of ASP was that you could include VBScript or JScript code instructions in the page executed on the Web server before the page was sent to the end user’s Web browser. This was an easy way to create dynamic Web pages customized based on instructions dictated by the developer. ASPused script between brackets and percentage signs to control server-side behaviors. A developer could then build an ASP page by starting with a set of static HTML. Any dynamic element needed by the page was defined using a scripting language (such as VBScript or JScript). When a user requested the page from the server by using a browser, the (an ISAPI application that provided a bridge between thescripting language and the Web server) would take hold of the page and define all the dynamic aspects of the page on-the-fly based on the programming logic specified in the script. After all the dynamic aspects of the page were defined, the result was an HTML page output to the browser of the requesting client.

INTRODUCTION

As the Web application model developed, more and more languages mixed inwith the static HTML to help manipulate the behavior and look of the output page. Over time, such a large number of languages, scripts, and plain text could be placed in a typical ASP page that developers began to refer to pages that used these features as spaghetti code. For example, having a page that used HTML, VBScript, JavaScript, Cascading Style Sheets, T-SQL, and more was quite possible....