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BEGINNING C# 7 Programming with Visual Studio® 2017

 

Benjamin Perkins
Jacob Vibe Hammer
Jon D. Reid







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ABOUT THE AUTHORS

BENJAMIN PERKINS (MBA, MCSD, ITIL) is currently employed at Microsoft in Munich, Germany, as a Senior Escalation Engineer. He has been working professionally in the IT industry for over two decades. He started computer programming with QBasic at the age of 11 on an Atari 1200XL desktop computer. He takes pleasure in the challenges that troubleshooting technical issues has to offer and savors the rewards of a well‐written program. After completing high school he joined the United States Army. After successfully completing his military service, he attended Texas A&M University in College Station, Texas, where he received a Bachelor of Business Administration in Management Information Systems.

His roles in the IT industry have spanned the entire spectrum including programmer, system architect, technical support engineer, team leader, and mid‐level management. While employed at Hewlett‐Packard, he received numerous awards, degrees, and certifications. He has a passion for technology and customer service and looks forward to troubleshooting and writing more world‐class technical solutions.

“My approach is to write code with support in mind, and to write it once correctly and completely so we do not have to come back to it again, except to enhance it.”

Benjamin is married to Andrea and has two wonderful children, Lea and Noa.

JACOB VIBE HAMMER helps develop solutions for the health care industry as a Senior Software Engineer at Systematic in Denmark. He started programming just about the time when he was able to spell the word “BASIC”—which, incidentally, is the first programming language he ever used. Since then, he has worked with numerous programming languages and solution architectures; however, since the turn of the century, he has worked primarily with the .NET platform. Today, his programming time is spent working primarily with C# and WPF, as well as toying with NoSQL databases. A Danish citizen, Jacob lives in Aarhus, Denmark, with his wife and two sons.

JON D. REID is a Product Solution Manager for IFS Field Service Management (www.IFSWORLD.com). He has coauthored a number of books, including Beginning Visual C# 2015, Fast Track C#, Pro Visual Studio .NET, and many others.

ABOUT THE TECHNICAL EDITOR

JOHN MUELLER is a freelance author and technical editor. He has writing in his blood, having produced 108 books and more than 600 articles to date. The topics range from networking to artificial intelligence and from database management to heads‐down programming. Some of his current books include topics such as Python for beginners, Python for data scientists, and Amazon Web Services. He has also written about algorithms and machine learning. His technical editing skills have helped more than 70 authors refine the content of their manuscripts. John has provided technical editing services to a number of computing magazines. Be sure to read John's blog at http://blog.johnmuellerbooks.com/.

CREDITS

SENIOR ACQUISITIONS EDITOR
Kenyon Brown

PROJECT EDITOR
Tom Dinse

TECHNICAL EDITOR
John Mueller

PRODUCTION EDITOR
Barath Kumar Rajasekaran

COPY EDITOR
First Edition Publishing Services

PRODUCTION MANAGER
Katie Wisor

MANAGER OF CONTENT ENABLEMENT AND OPERATIONS
Pete Gaughan

MARKETING MANAGER
Christie Hilbrich

BUSINESS MANAGER
Amy Knies

PROJECT COORDINATOR, COVER
Brent Savage

PROOFREADER
Nancy Bell

INDEXER
Johnna VanHoose Dinse

COVER DESIGNER
Wiley

COVER IMAGE
©Ben Clift Williams/EyeEm/Getty Images

ACKNOWLEDGMENTS

It takes a lot of work to get content into a presentable format for students and IT professionals to read and get value from. The authors indeed have technical knowledge and experiences to share, but without the technical writers, technical reviewers, developers, editors, publishers, graphic designers, the list goes on, providing their valuable input, a book of high quality could not be written. The rate of change occurs too quickly for an individual to perform all these tasks and still publish a book that is valid before the technology becomes stale. This is why authors worked together with a great team to get all the components of the book together quickly. It was done to ensure that the most up to date information gets to the reader while the features are still fresh and current. I would like to thank Tom Dinse for his great project management and technical review of the content as well as John Mueller for his technical review and suggestions throughout the process. Lastly, I would like to thank all the numerous people behind the scenes who helped get this book together.

INTRODUCTION

THE C# LANGUAGE WAS UNVEILED TO THE WORLD when Microsoft announced the first version of its .NET Framework in July 2000. Since then its popularity has rocketed, and it has arguably become the language of choice for desktop, web, cloud, and cross‐platform developers who use the .NET Framework. Part of the appeal of C# comes from its clear syntax, which derives from C/C++ but simplifies some things that have previously discouraged some programmers. Despite this simplification, C# has retained the power of C++, and there is now no reason not to move into C#. The language is not difficult and it's a great one to learn elementary programming techniques with. This ease of learning, combined with the capabilities of the .NET Framework, make C# an excellent way to start your programming career.

The latest release of C# is C# 7 (included with version 4.7 of the .NET Framework), which builds on the existing successes and adds even more attractive features. The latest release of Visual Studio (Visual Studio 2017) and the Visual Studio Code 2017 line of development tools also bring many tweaks and improvements to make your life easier and to dramatically increase your productivity.

This book is intended to teach you about all aspects of C# programming, including the language itself, desktop, cloud, and cross‐platform programming, making use of data sources, and some new and advanced techniques. You'll also learn about the capabilities of Visual Studio 2017 and all the ways that this product can aid your application development.

The book is written in a friendly, mentor‐style fashion, with each chapter building on previous ones, and every effort is made to ease you into advanced techniques painlessly. At no point will technical terms appear from nowhere to discourage you from continuing; every concept is introduced and discussed as required. Technical jargon is kept to a minimum, but where it is necessary, it, too, is properly defined and laid out in context.

The authors of this book are all experts in their field and are all enthusiastic in their passion for both the C# language and the .NET Framework. Nowhere will you find a group of people better qualified to take you under their collective wing and nurture your understanding of C# from first principles to advanced techniques. Along with the fundamental knowledge it provides, this book is packed full of helpful hints, tips, exercises, and full‐fledged example code (available for download on this book's web page at www.wrox.com and at https://github.com/benperk/BeginningCSharp7) that you will find yourself returning to repeatedly as your career progresses.

We pass this knowledge on without begrudging it and hope that you will be able to use it to become the best programmer you can be. Good luck, and all the best!

WHO THIS BOOK IS FOR

This book is for everyone who wants to learn how to program in C# using the .NET Framework. It is for absolute beginners who want to give programming a try by learning a clean, modern, elegant programming language. But it is also for people familiar with other programming languages who want to explore the .NET platform, as well as for existing .NET developers who want to give Microsoft's .NET flagship language a try.

WHAT THIS BOOK COVERS

The early chapters cover the language itself, assuming no prior programming experience. If you have programmed in other languages before, much of the material in these chapters will be familiar. Many aspects of C# syntax are shared with other languages, and many structures are common to practically all programming languages (such as looping and branching structures). However, even if you are an experienced programmer, you will benefit from looking through these chapters to learn the specifics of how these techniques apply to C#.

If you are new to programming, you should start from the beginning, where you will learn basic programming concepts and become acquainted with both C# and the .NET platform that underpins it. If you are new to the .NET Framework but know how to program, you should read Chapter 1 and then skim through the next few chapters before continuing with the application of the C# language. If you know how to program but haven't encountered an object‐oriented programming language before, you should read the chapters from Chapter 8 onward.

Alternatively, if you already know the C# language, you might want to concentrate on the chapters dealing with the most recent .NET Framework and C# language developments, specifically the chapters on collections, generics, and C# language enhancements (Chapters 11 and 12).

The chapters in this book have been written with a dual purpose in mind: They can be read sequentially to provide a complete tutorial in the C# language, and they can be dipped into as required reference material.

In addition to the core material, starting with Chapter 3 most chapters also include a selection of exercises at the end, which you can work through to ensure that you have understood the material. The exercises range from simple multiple choice or true/false questions to more complex exercises that require you to modify or build applications. The answers to all the exercises are provided in the Appendix. You can also find these exercises as part of the wrox.com code downloads on this book's page at www.wrox.com.

This book also gives plenty of love and attention to coincide with the release of C# 7 and .NET 4.7. Every chapter received an overhaul, with less relevant material removed, and new material added. All of the code has been tested against the latest version of the development tools used, and all of the screenshots have been retaken in Windows 10 to provide the most current windows and dialog boxes. New highlights of this edition include the following:

  • Additional and improved code examples for you to try out
  • Coverage of everything that's new in C# 7 and .NET 4.7
  • Examples of programming .NET Core and ASP.NET Core for running cross‐platform
  • Examples of programming cloud applications and using Azure SDK to create and access cloud resources

HOW THIS BOOK IS STRUCTURED

This book is divided into six sections:

  • Introduction—Purpose and general outline of the book's contents
  • The C# Language—Covers all aspects of the C# language, from the fundamentals to object‐oriented techniques
  • Windows Programming—How to write and deploy desktop applications with the Windows Presentation Foundation library (WPF)
  • Cloud and Cross‐Platform Programming—Cloud and cross‐platform application development and deployment, including the creation and consumption of a Web API
  • Data Access—How to use data in your applications, including data stored in files on your hard disk, data stored in XML format, and data in databases
  • Additional Techniques—An examination of some extra ways to use C# and the .NET Framework, including Windows Communication Foundation (WCF) and Universal Windows Applications

The following sections describe the chapters in the five major parts of this book.

The C# Language (Chapters 1– 13 )

Chapter 1 introduces you to C# and how it fits into the .NET landscape. You'll learn the fundamentals of programming in this environment and how Visual Studio 2017 (VS) fits in.

Chapter 2 starts you off with writing C# applications. You'll look at the syntax of C# and put the language to use with sample command‐line and Windows applications. These examples demonstrate just how quick and easy it can be to get up and running, and along the way you'll be introduced to the Visual Studio development environment and the basic windows and tools that you'll be using throughout the book.

Next, you'll learn more about the basics of the C# language. You'll learn what variables are and how to manipulate them in Chapter 3. You'll enhance the structure of your applications with flow control (looping and branching) in Chapter 4, and you'll see some more advanced variable types such as arrays in Chapter 5. In Chapter 6 you'll start to encapsulate your code in the form of functions, which makes it much easier to perform repetitive operations and makes your code much more readable.

By the beginning of Chapter 7 you'll have a handle on the fundamentals of the C# language, and you will focus on debugging your applications. This involves looking at outputting trace information as your applications are executed, and at how Visual Studio can be used to trap errors and lead you to solutions for them with its powerful debugging environment.

From Chapter 8 onward you'll learn about object‐oriented programming (OOP), starting with a look at what this term means and an answer to the eternal question, “What is an object?” OOP can seem quite difficult at first. The whole of Chapter 8 is devoted to demystifying it and explaining what makes it so great, and you won't actually deal with much C# code until the very end of the chapter.

Everything changes in Chapter 9, when you put theory into practice and start using OOP in your C# applications. This is where the true power of C# lies. You'll start by looking at how to define classes and interfaces, and then move on to class members (including fields, properties, and methods) in Chapter 10. At the end of that chapter you'll start to assemble a card game application, which is developed over several chapters and will help to illustrate OOP.

Once you've learned how OOP works in C#, Chapter 11 moves on to look at common OOP scenarios, including dealing with collections of objects, and comparing and converting objects. Chapter 12 takes a look at a very useful feature of C# that was introduced in .NET 2.0: generics, which enable you to create very flexible classes. Next, Chapter 13 continues the discussion of the C# language and OOP with some additional techniques, notably events, which become very important in, for example, Windows programming. Chapter 13 wraps up the fundamentals by focusing on C# language features that were introduced with versions 3.0, 4, 5, and 6 of the language.

Windows Programming (Chapters 14– 15 )

Chapter 14 starts by introducing you to what is meant by Windows programming and looks at how this is achieved in Visual Studio. It focuses on WPF as a tool that enables you to build desktop applications in a graphical way and assemble advanced applications with the minimum of effort and time. You'll start with the basics of WPF programming and build up your knowledge in both this chapter and Chapter 15, which demonstrates how you can use the wealth of controls supplied by the .NET Framework in your applications.

Cloud and Cross‐Platform Programming (Chapters 16– 19 )

Chapter 16 starts by describing what cloud programming is and discusses the cloud‐optimized stack. The cloud environment is not identical to the way programs have been traditionally coded, so a few cloud programming patterns are discussed and defined. To complete this chapter, you require an Azure account, which is free, so that you can create an App Service Web App. Then, using the Azure SDK with C#, you create and access a storage account from an ASP.NET 4.7 web application.

In Chapter 17, you learn how to create and deploy an ASP.NET Web API to the cloud and then consume the Web API from a similar ASP.NET 4.7 web application. The chapter ends discussing two of the most valuable features in the cloud, scaling and the optimal utilization of hardware resources.

Chapter 18 introduces .NET Standard and .NET Core, which are tools used for targeting any application type—for example WPF, Windows, and ASP.NET. An emerging application is one that can run cross‐platform such as on Linux or MacOS. The chapter provides instructions for installing .NET Core 2.0 and creating and implementing a .NET Standard library.

Chapter 19 describes ASP.NET and its many different types (e.g., ASP.NET Webforms, ASP.NET MVC, and ASP.NET Core). The exercises in this chapter utilize the .NET Standard library created in Chapter 18 from both an ASP.NET Webpage and an ASP.NET Core application.

Data Access (Chapters 20– 23 )

Chapter 20 looks at how your applications can save and retrieve data to disk, both as simple text files and as more complex representations of data. You'll also learn how to compress data and how to monitor and act on file system changes.

In Chapter 21 you'll learn about the de facto standard for data exchange—namely XML—and a rapidly emerging format called JSON. By this point in the book, you'll have touched on XML several times in preceding chapters, but this chapter lays out the ground rules and shows you what all the excitement is about.

The remainder of this part looks at LINQ, which is a query language built in to the latest versions of the .NET Framework. You start in Chapter 22 with a general introduction to LINQ, and then you will use LINQ to access a database and other data in Chapter 23.

Additional Techniques (Chapters 24– 25 )

Chapter 24 is an introduction to Windows Communication Foundation (WCF), which provides you with the tools you need for enterprise‐level programmatic access to information and capabilities across local networks and the Internet. You will see how you can use WCF to expose complex data and functionality to web and desktop applications in a platform‐independent way.

Chapter 25 shows you how you can create Universal Windows Apps, which are new to Windows. This chapter builds on the foundation of Chapters 14 and 15 to show you how to create Windows Apps that can run on all windows platforms.

WHAT YOU NEED TO USE THIS BOOK

The code and descriptions of C# and the .NET Framework in this book apply to C# 7 and .NET 4.7. You don't need anything other than the Framework to understand this aspect of the book, but many of the examples require a development tool. This book uses Visual Studio Community 2017 as its primary development tool. Use Visual Studio Community 2017 to create Windows, cloud, and cross‐platform applications as well as SQL Server Express for applications that access databases. Some functionality is available only in Visual Studio 2017, but this won't stop you from working through any of the examples in this book.

The source code for the samples is available for download from this book's page on www.wrox.com and at https://github.com/benperk/BeginningCSharp7.

CONVENTIONS

To help you get the most from the text and keep track of what's happening, we've used a number of conventions throughout the book.

As for styles in the text:

  • We italicize new terms and important words when we introduce them.
  • We show keyboard strokes like this: Ctrl+A.
  • We show file names, URLs, and code within the text like so: persistence.properties

We present code in two different ways:

We use a monofont type with no highlighting for most code examples.
We use bold to emphasize code that is particularly important in the present
context or to show changes from a previous code snippet.

SOURCE CODE

As you work through the examples in this book, you may choose either to type in all the code manually, or to use the source code files that accompany the book. All the source code used in this book is available for download on this book's page at www.wrox.com and at https://github.com/benperk/BeginningCSharp7.

You can also search for the book at www.wrox.com by ISBN (the ISBN for this book is 978‐1‐119‐45868‐5) to find the code. A complete list of code downloads for all current Wrox books is available at www.wrox.com/dynamic/books/download.aspx.

Most of the code on www.wrox.com is compressed in a .ZIP, .RAR archive, or similar archive format appropriate to the platform. Once you download the code, just decompress it with an appropriate compression tool.

ERRATA

We make every effort to ensure that there are no errors in the text or in the code. However, no one is perfect, and mistakes do occur. If you find an error in one of our books, like a spelling mistake or faulty piece of code, we would be very grateful for your feedback. By sending in errata, you may save another reader hours of frustration, and at the same time, you will be helping us provide even higher quality information.

To find the errata page for this book, go to this book's page at www.wrox.com and click the Errata link. On this page you can view all errata that has been submitted for this book and posted by Wrox editors.

If you don't spot “your” error on the Book Errata page, go to www.wrox.com/contact/techsupport.shtml and complete the form there to send us the error you have found. We'll check the information and, if appropriate, post a message to the book's errata page and fix the problem in subsequent editions of the book.

PART I
The C# Language

  • CHAPTER 1: Introducing C#
  • CHAPTER 2: Writing a C# Program
  • CHAPTER 3: Variables and Expressions
  • CHAPTER 4: Flow Control
  • CHAPTER 5: More about Variables
  • CHAPTER 6: Functions
  • CHAPTER 7: Debugging and Error Handling
  • CHAPTER 8: Introduction to Object-Oriented Programming
  • CHAPTER 9: Defining Classes
  • CHAPTER 10: Defining Class Members
  • CHAPTER 11: Collections, Comparisons, and Conversions
  • CHAPTER 12: Generics
  • CHAPTER 13: Additional C# Techniques