C# A Programmer's Introduction, 1/e: Tour of the Book (Continued)

Chapter 9-Object-Oriented Programming: Inheritance

In this chapter, we discuss inheritance-a form of software reusability in which classes (called derived classes) are created by absorbing attributes and methods of existing classes (called base classes). The inherited class (i.e., the derived class) can contain additional attributes and methods. We show how finding the commonality between classes of objects can reduce the amount of work it takes to build large software systems. These proven techniques help programmers create and maintain software systems. A detailed case study demonstrates software reuse and good programming techniques by finding the commonality among a three-level inheritance hierarchy: The Point, Circle and Cylinder classes. We discuss the software engineering benefits of object-oriented programming. Crucial object-oriented programming concepts, such as creating and extending classes, are presented in this chapter.

Chapter 10-Exception Handling

Exception handling is one of the most important topics in C# from the standpoint of building mission-critical and business-critical applications. People can enter incorrect data, data can be corrupted and clients can try to access records that do not exist or are restricted. A simple division-by-zero error may cause a calculator program to crash, but what if such an error occurs in the navigation system of an airplane while it is in flight? In some cases, the results of program failure could be disastrous. Programmers need to know how to recognize the errors (exceptions) that could occur in software components and handle those exceptions effectively, allowing programs to deal with problems and continue executing instead of "crashing." Programmers who construct software systems from reusable components built by other programmers must deal with the exceptions that those components may "throw." This chapter covers the details of C# exception handling, the termination model of exception handling, throwing and catching exceptions, and FCL class Exception.

Chapter 11-Graphical User Interface Concepts

Chapter 11 explains how to add sophisticated GUIs to programs. By using the techniques of rapid application development (RAD), programmers can create GUIs from reusable components, rather than explicitly programming every detail. The Visual Studio .NET IDE makes developing GUIs even easier by allowing the programmer to position components in a window through so-called visual programming. We discuss how to construct user interfaces with Windows Forms controls such as labels, buttons, textboxes and picture boxes. We also introduce events, which are messages sent by a program to signal to an object or a set of objects that an action has occurred. Events most commonly are used to signal user interactions with GUI controls, but also can signal internal actions in a program. We overview event handling and discuss how to handle events specific to controls, the keyboard and the mouse. Tips are included throughout the chapter to help the programmer create visually appealing, well-organized and consistent GUIs. The last section of this chapter introduces visual inheritance, which enables programmers to combine the GUI concepts presented in this chapter with the object-oriented concepts presented in Chapter 9 to create user interfaces that can be used and extended by other programmers.

Chapter 12-Multithreading

Users have come to expect much from applications. Users want to download files from the Internet, listen to music, print documents and browse the Web-all at the same time! To do this, programmers need a feature called multithreading, which allows applications to perform multiple activities concurrently. The .NET Framework includes built-in capabilities to enable multithreaded applications, while shielding programmers from complex details. The .NET languages are better equipped to deal with more sophisticated multimedia, network-based and multiprocessor-based applications than those languages that do not have multithreading features. This chapter introduces the FCL's threading classes and covers threads, thread life-cycles, time-slicing, scheduling and priorities. This chapter lays the foundation for creating the multithreaded programs that clients demand.

Chapter 13-Strings and Characters

In this chapter, we discuss the processing of words, sentences, characters and groups of characters. In C#, strings (groups of characters) are objects. This is yet another benefit of C#'s emphasis on object-oriented programming. Objects of type string contain methods that can copy, search, extract substrings and concatenate strings with one another. We introduce class StringBuilder, which defines string-like objects that can be modified after initialization. As an interesting example of strings, we create a card shuffling-and-dealing simulation.

Chapter 14-Graphics

In this chapter, we discuss GDI+ (an extension of the Graphics Device Interface-GDI), the Windows service that provides the graphical features used by .NET applications. The extensive graphical capabilities of GDI+ can make programs more visual and fun to create and use. We discuss C#'s treatment of graphics objects and color control. We also discuss how to draw lines, rectangles and ovals. The chapter also demonstrates how to use various pens and brushes to create color effects, and introduces techniques for turning text-only applications into exciting, aesthetically pleasing programs that even novice programmers can write with ease.

Chapter 15-Files and Streams

Imagine a program that could not save data to a file. Once the program is closed, all the work performed in the program is lost forever. For this reason, this chapter is one of the most important for programmers who will be developing commercial applications. We introduce FCL classes for file inputting and outputting data. A detailed example demonstrates these concepts by allowing the user to read and write bank account information to and from files. We introduce the FCL classes and methods that help perform input and output conveniently-they demonstrate the power of object-oriented programming and reusable classes. This chapter lays the groundwork for the material presented in Chapter 20, Networking: Streams-Based Sockets.

Chapter 16-Database, SQL and ADO .NET

Data storage and access are integral to creating powerful software applications. This chapter discusses .NET support for database manipulation. Today's most popular database systems are relational databases. In this chapter, we introduce the Structured Query Language (SQL) for performing queries on relational databases. We introduce ActiveX Data Objects ADO .NET-an extension of ADO that enables .NET applications to access and manipulate databases. We show the reader how to create database connections, using tools provided in Visual Studio .NET, and how to use some of the classes in namespace System.Data to query a database.