| The .NET Framework contains such a large selection of topics that it is impossible to cover all of them in a single book of any depth. This section introduces the focus of this book, and provides an overview of the contents and conventions used in the text. The end of this section describes the online forum available for any questions or comments on the book, and explains how the source code used in the book can be downloaded from the Internet.
Before we discuss the book specifically, we should introduce the concept of namespaces. A namespace defines a group, or scope, of related classes, structures, and other types. A namespace is a bit like a family: it defines a group of distinct members with a common name and some shared sense of purpose.
All objects in the .NET Framework, and indeed in C# itself, are organized into namespaces. The System namespace, for example, includes objects related to the framework itself, and most namespaces defined by .NET are nested within the System namespace. The System.Windows namespace defines types and namespaces related to the Windows operating system, while the System.Web namespace defines types and namespaces related to web pages and servers.
This organization into namespaces permits two objects with the same base name to be distinct, much like two people can both share the same first name. For example, the Button class in the System.Web.UI.WebControls namespace represents a button on a web page, while the Button class in the System.Windows.Forms namespace represents a button in an application window. Other namespaces in .NET include the System.IO namespace for file and directory related objects, the System. Data namespace for database-related objects, the System.Drawing namespace for graphical objects, and the System.Security namespace for security objects. An overview of the more commonly used namespaces in .NET is provided in appendix B. |
