Programming C# 12: Build Cloud, Web, and Desktop Applications

Cover....1

Copyright....4

Table of Contents....7

Preface....19

Who This Book Is For....19

Conventions Used in This Book....19

Using Code Examples....20

O’Reilly Online Learning....21

How to Contact Us....21

Acknowledgments....22

Chapter 1. Introducing C#....23

Why C#?....24

Managed Code and the CLR....26

C# Prefers Generality to Specialization....28

C# Standards and Implementations....29

Many .NETs....29

Release Cycles and Long Term Support....31

Targeting Multiple .NET Runtimes....32

Visual Studio, Visual Studio Code, and JetBrains Rider....34

Anatomy of a Simple Program....37

Writing a Unit Test....42

Namespaces....47

Classes....52

Unit Tests....54

Summary....55

Chapter 2. Basic Coding in C#....57

Local Variables....58

Scope....64

Variable Name Ambiguity....65

Local Variable Instances....67

Statements and Expressions....68

Statements....68

Expressions....69

Comments and Whitespace....76

Preprocessing Directives....78

Compilation Symbols....78

#error and #warning....80

#line....80

#pragma....81

#nullable....82

#region and #endregion....82

Fundamental Data Types....83

Numeric Types....83

Booleans....95

Strings and Characters....95

Tuples....108

Tuple Deconstruction....110

Dynamic....112

Object....113

Operators....113

Flow Control....119

Boolean Decisions with if Statements....120

Multiple Choice with switch Statements....122

Loops: while and do....124

C-Style for Loops....125

Collection Iteration with foreach Loops....127

Patterns....128

Combining and Negating Patterns....135

Relational Patterns....136

Getting More Specific with when....137

Patterns in Expressions....137

Summary....140

Chapter 3. Types....141

Classes....141

Initialization Inputs....144

Static Members....146

Static Classes....148

Records....150

References and Nulls....156

Banishing Null with Non-Nullable References....160

Structs....168

When to Write a Value Type....173

Guaranteeing Immutability....177

Record Structs....178

Class, Structs, Records, or Tuples?....179

Members....181

Accessibility....181

Fields....181

Constructors....184

Deconstructors....197

Methods....199

Properties....216

Operators....229

Events....232

Nested Types....232

Interfaces....234

Default Interface Implementation....236

Static Virtual Members....238

Enums....240

Other Types....243

Anonymous Types....244

Partial Types and Methods....247

Summary....248

Chapter 4. Generics....249

Generic Types....250

Constraints....252

Type Constraints....253

Reference Type Constraints....256

Value Type Constraints....258

Value Types All the Way Down with Unmanaged Constraints....259

Not Null Constraints....259

Other Special Type Constraints....259

Multiple Constraints....260

Zero-Like Values....260

Generic Methods....262

Type Inference....263

Generic Math....264

Generic Math Interfaces....267

Numeric Category Interfaces....267

Operator Interfaces....272

Function Interfaces....273

Parsing and Formatting....274

Generics and Tuples....275

Summary....276

Chapter 5. Collections....277

Arrays....277

Array Initialization....281

Searching and Sorting....284

Multidimensional Arrays....288

Copying and Resizing....292

List....293

List and Sequence Interfaces....297

Implementing Lists and Sequences....304

Implementing IEnumerable with Iterators....304

Collection....308

ReadOnlyCollection....309

Addressing Elements with Index and Range Syntax....310

System.Index....311

System.Range....313

Supporting Index and Range in Your Own Types....316

Dictionaries....318

Sorted Dictionaries....321

Sets....323

Queues and Stacks....324

Linked Lists....325

Concurrent Collections....326

Immutable Collections....327

Frozen Collections....330

Summary....331

Chapter 6. Inheritance....333

Inheritance and Conversions....335

Interface Inheritance....338

Generics....339

Covariance and Contravariance....341

System.Object....347

The Ubiquitous Methods of System.Object....347

Accessibility and Inheritance....348

Virtual Methods....350

Abstract Methods....352

Inheritance and Library Versioning....354

Static Virtual Methods....360

Default Constraints....361

Sealed Methods and Classes....364

Accessing Base Members....366

Inheritance and Construction....367

Primary Constructors....369

Mandatory Properties....371

Field Initialization....372

Record Types....374

Records, Inheritance, and the with Keyword....376

Special Base Types....377

Summary....378

Chapter 7. Object Lifetime....379

Garbage Collection....380

Determining Reachability....382

Accidentally Defeating the Garbage Collector....384

Weak References....387

Reclaiming Memory....390

Lightening the Load with Inline Arrays....396

Garbage Collector Modes....398

Temporarily Suspending Garbage Collections....401

Accidentally Defeating Compaction....402

Forcing Garbage Collections....405

Destructors and Finalization....406

IDisposable....409

Optional Disposal....417

Boxing....418

Boxing Nullable....423

Summary....424

Chapter 8. Exceptions....425

Exception Sources....427

Exceptions from APIs....428

Failures Detected by the Runtime....431

Handling Exceptions....432

Exception Objects....433

Multiple catch Blocks....435

Exception Filters....436

Nested try Blocks....437

finally Blocks....439

Throwing Exceptions....441

Rethrowing Exceptions....443

Failing Fast....446

Exception Types....446

Custom Exceptions....448

Unhandled Exceptions....450

Summary....452

Chapter 9. Delegates, Lambdas, and Events....453

Delegate Types....454

Creating a Delegate....456

Multicast Delegates....460

Invoking a Delegate....461

Common Delegate Types....463

Type Compatibility....465

Behind the Syntax....467

Anonymous Functions....469

Lambdas and Default Arguments....473

Captured Variables....476

Lambdas and Expression Trees....484

Events....486

Standard Event Delegate Pattern....488

Custom Add and Remove Methods....489

Events and the Garbage Collector....491

Events Versus Delegates....493

Delegates Versus Interfaces....494

Summary....495

Chapter 10. LINQ....497

Query Expressions....498

How Query Expressions Expand....501

Deferred Evaluation....503

LINQ, Generics, and IQueryable....506

Standard LINQ Operators....508

Filtering....510

Select....513

SelectMany....516

Ordering....519

Containment Tests....522

Specific Items and Subranges....523

Whole-Sequence, Order-Preserving Operations....528

Aggregation....529

Grouping....534

Conversion....539

Sequence Generation....544

Other LINQ Implementations....544

Entity Framework Core....544

Parallel LINQ (PLINQ)....545

LINQ to XML....545

IAsyncEnumerable....546

Reactive Extensions....546

Summary....546

Chapter 11. Rx: Reactive Extensions....547

Fundamental Interfaces....549

IObserver....551

IObservable....552

Publishing and Subscribing with Delegates....558

Creating an Observable Source with Delegates....558

Subscribing to an Observable Source with Delegates....562

Sequence Builders....563

Empty....563

Never....563

Return....564

Throw....564

Range....564

Repeat....565

Generate....565

LINQ Queries....566

Grouping Operators....568

Join Operators....570

SelectMany Operator....573

Aggregation and Other Single-Value Operators....574

Concat Operator....575

Rx Query Operators....575

Merge....576

Windowing Operators....577

The Scan Operator....584

The Amb Operator....586

DistinctUntilChanged....587

Schedulers....587

Specifying Schedulers....588

Built-in Schedulers....590

Subjects....591

Subject....592

BehaviorSubject....592

ReplaySubject....593

AsyncSubject....593

Adaptation....593

IEnumerable and IAsyncEnumerable....594

.NET Events....596

Asynchronous APIs....597

Timed Sequences....599

Timed Sources....599

Timed Operators....600

Timed Windowing Operators....602

Reaqtor—Rx as a Service....603

Summary....604

Chapter 12. Assemblies and Deployment....605

Anatomy of an Assembly....606

.NET Metadata....607

Resources....607

Multifile Assemblies....607

Other PE Features....608

Type Identity....609

Deployment....613

Framework-Dependent....613

Self-Contained....615

Trimming....616

Ahead-of-Time (AOT) Compilation....617

Loading Assemblies....620

Assembly Resolution....621

Explicit Loading....623

Isolation and Plug-ins with AssemblyLoadContext....625

Assembly Names....627

Strong Names....627

Version....630

Version Numbers and Assembly Loading....632

Culture....633

Protection....637

Target Frameworks and .NET Standard....638

Summary....640

Chapter 13. Reflection....641

Reflection Types....643

Assembly....644

Module....648

MemberInfo....648

Type and TypeInfo....651

Generic Types....655

MethodBase, ConstructorInfo, and MethodInfo....657

ParameterInfo....658

FieldInfo....659

PropertyInfo....659

EventInfo....660

Reflection Contexts....660

Summary....662

Chapter 14. Attributes....663

Applying Attributes....663

Attribute Targets....666

Compiler-Handled Attributes....669

CLR-Handled Attributes....677

Debugging Attributes....680

Build-Time Attributes....681

Defining and Consuming Attributes....683

Attribute Types....684

Retrieving Attributes....685

Metadata-Only Load....687

Generic Attribute Types....688

Summary....689

Chapter 15. Files and Streams....691

The Stream Class....692

Position and Seeking....694

Flushing....695

Copying....696

Length....696

Disposal....697

Asynchronous Operation....697

Concrete Stream Types....698

One Type, Many Behaviors....700

Text-Oriented Types....701

TextReader and TextWriter....702

Concrete Reader and Writer Types....704

Encoding....706

Files and Directories....709

FileStream Class....710

File Class....712

Directory Class....714

Path Class....714

Serialization....715

BinaryReader, BinaryWriter, and BinaryPrimitives....716

CLR Serialization....717

JSON....718

Summary....728

Chapter 16. Multithreading....729

Threads....729

Threads, Variables, and Shared State....731

Thread-Local Storage....734

The Thread Class....736

The Thread Pool....738

Thread Affinity and SynchronizationContext....740

ExecutionContext....743

Synchronization....744

Monitors and the lock Keyword....745

Other Synchronization Primitives....752

Interlocked....752

Lazy Initialization....754

Other Class Library Concurrency Support....756

Tasks....758

The Task and Task Classes....758

Continuations....764

Schedulers....766

Error Handling....768

Custom Threadless Tasks....768

Parent/Child Relationships....770

Composite Tasks....770

Other Asynchronous Patterns....771

Cancellation....772

Parallelism....773

The Parallel Class....773

Parallel LINQ....775

TPL Dataflow....775

Summary....775

Chapter 17. Asynchronous Language Features....777

Asynchronous Keywords: async and await....778

Execution and Synchronization Contexts....782

Multiple Operations and Loops....784

Returning a Task....791

Applying async to Nested Methods....793

The await Pattern....793

Error Handling....798

Validating Arguments....800

Singular and Multiple Exceptions....802

Concurrent Operations and Missed Exceptions....803

Summary....804

Chapter 18. Memory Efficiency....807

(Don’t) Copy That....808

Representing Sequential Elements with Span....812

Utility Methods....816

Collection Expressions and Spans....817

Pattern Matching....817

Stack Only....818

Using ref with Fields....819

Representing Sequential Elements with Memory....823

ReadOnlySequence....824

Processing Data Streams with Pipelines....824

Processing JSON in ASP.NET Core....827

Summary....832

Index....835

About the Author....875

Colophon....875

C# is undeniably one of the most versatile programming languages available to engineers today. With this comprehensive guide, you'll learn just how powerful the combination of C# and .NET can be. Author Ian Griffiths guides you through C# 12.0 and .NET 8 fundamentals and techniques for building cloud, web, and desktop applications.

Designed for experienced programmers, this book provides many code examples to help you work with the nuts and bolts of C#, such as generics, LINQ, and asynchronous programming features. You'll get up to speed on .NET 8 and the latest C# 11.0 and 12.0 additions, including generic math, new polymorphism options, enhanced pattern matching, and new features designed to improve productivity.C# has now existed for around two decades. It has grown steadily in both power and size, but Microsoft has always kept the essential characteristics intact. Each new capability is designed to integrate cleanly with the rest, enhancing the language without turning it into an incoherent bag of miscellaneous features. Even though C# continues to be a fairly straightforward language at its heart, there is a great deal more to say about it now than in its first incarnation. Because there is so much ground to cover, this book expects a certain level of technical ability from its readers.

The C# programming language (pronounced “see sharp”) is used for many kinds of applications, including websites, cloud-based systems, artificial intelligence, IoT devices, desktop applications, embedded controllers, mobile apps, games, and command-line utilities. C#, along with the supporting runtime, libraries, and tools known collectively as .NET, has been center stage for Windows developers for over 20 years. Today, .NET is cross-platform and open source, enabling applications and services written in C# to run on operating systems including Android, iOS, macOS, and Linux, as well as on Windows.

C# 11.0 and 12.0 have gained performance-oriented features including generic math, and improved control over memory handling for performance-sensitive low-level code. Every new .NET release has improved execution speed, but there have also been significant reductions in startup times, memory footprint, and binary size. This, along with improved support for containerization, enhances .NET’s fit for modern cloud development. There have also been significant improvements for cross-platform client-side development, thanks to Blazor and .NET MAUI (Multi-platform App UI). .NET has supported ARM and WebAssembly (WASM) for many years, but continuous recent improvements for those targets are important for cloud, mobile, and web development.

This book helps you:

• Understand how .NET has changed in recent releases and learn what it means for application development
• Select the appropriate C# language features for any task
• Learn when to use the new features and when to stick with older ones
• Examine the range of functionality in .NET's class libraries
• Apply these class libraries to practical programming tasks
• Explore numerous small additions to .NET that improve expressiveness

Who This Book Is For:

I have written this book for experienced developers—I’ve been programming for years, and I set out to make this the book I would want to read if that experience had been in other languages, and I were learning C# today. Whereas earlier editions explained some basic concepts such as classes, polymorphism, and collections, I am assuming that readers will already know what these are. The early chapters still describe how C# presents these common ideas, but the focus is on the details specific to C#, rather than the broad concepts.