| ASP.NET, which is implemented in the System.Web namespace and its various subnamespaces, collectively represents the features used in developing both Web applications and XML Web services. As a component developer in the ASP.NET space, you'll be using classes from these namespaces in your component implementation. Table 1-1 lists these namespaces and their associated functionality. Table 1-1. ASP.NET Namespaces | Namespace | Functionality | | System.Web | Contains classes such as HttpContext , HttpRequest , and HttpResponse , which are used to implement the HTTP runtime, its basic request processing architecture, and the commonly used intrinsic objects. It also contains other interface definitions (such as IHttpModule and IHttpHandler ) that define the extensible architecture of ASP.NET request processing logic. | | System.Web.UI , System.Web.UI.HtmlControls , System.Web.UI.WebControls | Collectively form the page framework, the control architecture, and the standard ASP.NET controls. As a single unit, these namespaces implement the feature commonly referred to as Web Forms . Chapter 2, "Page Programming Model," discusses the page framework in greater detail. Part II and Part III of this book, "Server Controls ”First Steps" and "Server Controls ”Nuts and Bolts," cover the technical details of extending this page framework. | | System.Web.Services | Provides the functionality used in the implementation, description, and discovery of XML Web services developed in the form of .asmx files. Chapter 18, "XML Web Services," discusses how to incorporate XML Web services into controls. | | System.Web.Caching | Provides the implementation of an in-memory caching system that holds cached data based on custom dependency and expiration rules. This namespace can be used to optimize the performance and responsiveness of Web applications. The caching system is also used by the output caching functionality of user controls, as described in Chapter 4, " User Controls: From Page to Control." | | System.Web.SessionState | Provides an implementation of the Session state object. Session state is scoped to a single user session, and its data can be held either in memory or in a database using SQL Server across multiple requests . | | System.Web.Security | Provides the implementation of various authentication mechanisms commonly used by Web applications, such as forms-based authentication, Microsoft Windows authentication, and Microsoft Passport authentication. | | System.Web.Mail | A utility namespace in ASP.NET that enables the incorporation of email delivery functionality using Simple Mail Transfer Protocol (SMTP). |  |
