C# 9.0 and .NET 5 – Modern Cross-Platform Development

C# 9.0 and .NET 5 – Modern Cross-Platform Development

Table of Contents

Chapter 1: Hello, C#! Welcome, .NET! 1

Setting up your development environment 2
Using Visual Studio Code for cross-platform development 2
Using GitHub Codespaces for development in the cloud 3
Using Visual Studio 2019 for Windows app development 4
Using Visual Studio for Mac for mobile development 4
Recommended tools for chapters 4
Deploying cross-platform 5
Understanding Microsoft Visual Studio Code versions 5
Downloading and installing Visual Studio Code 7
Installing other extensions 8
Understanding .NET 8
Understanding .NET Framework 8
Understanding the Mono and Xamarin projects 9
Understanding .NET Core 9
Understanding .NET 5 and the journey to one .NET 10
Understanding .NET support 11
Understanding .NET Runtime and .NET SDK versions 12
Removing old versions of .NET 13
What is different about .NET Core and .NET 5? 14
Understanding .NET Standard 15
.NET platforms and tools used by the book editions 16
Understanding intermediate language 17
Comparing .NET technologies 17
Building console apps using Visual Studio Code 17
Writing code using Visual Studio Code 18
Compiling and running code using the dotnet CLI 20
Writing top-level programs 20
Downloading solution code from the GitHub repository 21
Using Git with Visual Studio Code 21
Cloning the book solution code repository 22
Looking for help 22
Reading Microsoft documentation 22
Getting help for the dotnet tool 22
Getting definitions of types and their members 23
Looking for answers on Stack Overflow 25
Searching for answers using Google 26
Subscribing to the official .NET blog 26
Scott Hanselman's videos 26
Practicing and exploring 27
Exercise 1.1 – Test your knowledge 27
Exercise 1.2 – Practice C# anywhere 27
Exercise 1.3 – Explore topics 27
Summary 28

Chapter 2: Speaking C# 29

Introducing C# 29
Understanding language versions and features 30
C# 1.0 30
C# 2.0 30
C# 3.0 30
C# 4.0 31
C# 5.0 31
C# 6.0 31
C# 7.0 31
C# 7.1 32
C# 7.2 32
C# 7.3 32
C# 8.0 32
C# 9.0 33
Discovering your C# compiler versions 33
Enabling a specific language version compiler 35
Understanding C# basics 36
Understanding C# grammar 37
Statements 37
Comments 37
Blocks 38
Understanding C# vocabulary 38
Changing the color scheme for syntax 38
Comparing programming languages to human languages 39
Help for writing correct code 39
Verbs are methods 40
Nouns are types, fields, and variables 40
Revealing the extent of the C# vocabulary 41
Working with variables 43
Naming things and assigning values 44
Literal values 44
Storing text 44
Understanding verbatim strings 45
Storing numbers 46
Storing whole numbers 46
Storing real numbers 48
Writing code to explore number sizes 48
Comparing double and decimal types 49
Storing Booleans 51
Using Visual Studio Code workspaces 51
Storing any type of object 52
Storing dynamic types 53
Declaring local variables 54
Specifying and inferring the type of a local variable 54
Using target-typed new to instantiate objects 55
Getting default values for types 55
Storing multiple values 56
Working with null values 57
Making a value type nullable 57
Understanding nullable reference types 58
Enabling nullable and non-nullable reference types 59
Declaring non-nullable variables and parameters 59
Checking for null 61
Exploring console applications further 62
Displaying output to the user 62
Formatting using numbered positional arguments 62
Formatting using interpolated strings 63
Understanding format strings 63
Getting text input from the user 65
Importing a namespace 65
Simplifying the usage of the console 66
Getting key input from the user 66
Getting arguments 67
Setting options with arguments 69
Handling platforms that do not support an API 70
Practicing and exploring 71
Exercise 2.1 – Test your knowledge 71
Exercise 2.2 – Practice number sizes and ranges 71
Exercise 2.3 – Explore topics 72
Summary 72

Chapter 3: Controlling Flow and Converting Types 73

Operating on variables 73
Unary operators 74
Binary arithmetic operators 75
Assignment operators 76
Logical operators 76
Conditional logical operators 78
Bitwise and binary shift operators 79
Miscellaneous operators 80
Understanding selection statements 81
Branching with the if statement 81
Why you should always use braces with if statements 82
Pattern matching with the if statement 83
Branching with the switch statement 83
Pattern matching with the switch statement 85
Simplifying switch statements with switch expressions 87
Understanding iteration statements 88
Looping with the while statement 88
Looping with the do statement 88
Looping with the for statement 89
Looping with the foreach statement 90
Understanding how foreach works internally 90
Casting and converting between types 91
Casting numbers implicitly and explicitly 91
Converting with the System.Convert type 93
Rounding numbers 94
Understanding the default rounding rules 94
Taking control of rounding rules 95
Converting from any type to a string 95
Converting from a binary object to a string 96
Parsing from strings to numbers or dates and times 97
Avoiding exceptions using the TryParse method 98
Handling exceptions when converting types 99
Wrapping error-prone code in a try block 99
Catching all exceptions 100
Catching specific exceptions 101
Checking for overflow 102
Throwing overflow exceptions with the checked statement 103
Disabling compiler overflow checks with the unchecked statement 104
Practicing and exploring 105
Exercise 3.1 – Test your knowledge 106
Exercise 3.2 – Explore loops and overflow 106
Exercise 3.3 – Practice loops and operators 106
Exercise 3.4 – Practice exception handling 107
Exercise 3.5 – Test your knowledge of operators 108
Exercise 3.6 – Explore topics 108
Summary 108

Chapter 4: Writing, Debugging, and Testing Functions 109

Writing functions 109
Writing a times table function 110
Writing a function that returns a value 112
Writing mathematical functions 114
Converting numbers from cardinal to ordinal 114
Calculating factorials with recursion 116
Documenting functions with XML comments 119
Using lambdas in function implementations 120
Debugging during development 123
Creating code with a deliberate bug 123
Setting a breakpoint 124
Navigating with the debugging toolbar 125
Debugging windows 126
Stepping through code 126
Customizing breakpoints 127
Logging during development and runtime 128
Instrumenting with Debug and Trace 129
Writing to the default trace listener 130
Configuring trace listeners 131
Switching trace levels 132
Unit testing functions 135
Creating a class library that needs testing 135
Writing unit tests 137
Running unit tests 138
Practicing and exploring 139
Exercise 4.1 – Test your knowledge 139
Exercise 4.2 – Practice writing functions with debugging and unit testing 140
Exercise 4.3 – Explore topics 140
Summary 140

Chapter 5: Building Your Own Types with Object-Oriented Programming 141

Talking about object-oriented programming 141
Building class libraries 142
Creating a class library 142
Defining a class 143
Understanding members 144
Instantiating a class 145
Referencing an assembly 145
Importing a namespace to use a type 146
Managing multiple files 146
Understanding objects 147
Inheriting from System.Object 147
Storing data within fields 148
Defining fields 148
Understanding access modifiers 149
Setting and outputting field values 149
Storing a value using an enum type 150
Storing multiple values using an enum type 152
Storing multiple values using collections 153
Making a field static 154
Making a field constant 155
Making a field read-only 156
Initializing fields with constructors 157
Setting fields with default literals 158
Writing and calling methods 160
Returning values from methods 160
Combining multiple returned values using tuples 161
Naming the fields of a tuple 162
Inferring tuple names 163
Deconstructing tuples 163
Defining and passing parameters to methods 164
Overloading methods 164
Passing optional parameters and naming arguments 165
Controlling how parameters are passed 167
Understanding ref returns 168
Splitting classes using partial 168
Controlling access with properties and indexers 169
Defining read-only properties 169
Defining settable properties 171
Defining indexers 172
Pattern matching with objects 173
Creating and referencing a .NET 5 class library 173
Defining flight passengers 174
Enhancements to pattern matching in C# 9 176
Working with records 177
Init-only properties 177
Understanding records 178
Simplifying data members 179
Positional records 179
Practicing and exploring 180
Exercise 5.1 – Test your knowledge 180
Exercise 5.2 – Explore topics 181
Summary 181

Chapter 6: Implementing Interfaces and Inheriting Classes 183

Setting up a class library and console application 184
Simplifying methods 186
Implementing functionality using methods 186
Implementing functionality using operators 188
Implementing functionality using local functions 189
Raising and handling events 190
Calling methods using delegates 190
Defining and handling delegates 191
Defining and handling events 193
Implementing interfaces 194
Common interfaces 194
Comparing objects when sorting 195
Comparing objects using a separate class 197
Defining interfaces with default implementations 198
Making types safely reusable with generics 200
Working with generic types 202
Working with generic methods 203
Managing memory with reference and value types 204
Working with struct types 205
Releasing unmanaged resources 207
Ensuring that Dispose is called 209
Inheriting from classes 210
Extending classes to add functionality 210
Hiding members 211
Overriding members 212
Preventing inheritance and overriding 213
Understanding polymorphism 214
Casting within inheritance hierarchies 215
Implicit casting 215
Explicit casting 215
Avoiding casting exceptions 216
Inheriting and extending .NET types 217
Inheriting exceptions 217
Extending types when you can't inherit 219
Using static methods to reuse functionality 219
Using extension methods to reuse functionality 220
Practicing and exploring 221
Exercise 6.1 – Test your knowledge 221
Exercise 6.2 – Practice creating an inheritance hierarchy 222
Exercise 6.3 – Explore topics 222
Summary 223

Chapter 7: Understanding and Packaging .NET Types 225

Introducing .NET 5 225
.NET Core 1.0 226
.NET Core 1.1 227
.NET Core 2.0 227
.NET Core 2.1 227
.NET Core 2.2 228
.NET Core 3.0 228
.NET 5.0 228
Improving performance from .NET Core 2.0 to .NET 5 229
Understanding .NET components 229
Understanding assemblies, packages, and namespaces 230
Understanding dependent assemblies 230
Understanding the Microsoft .NET project SDKs 231
Understanding NuGet packages 232
Understanding frameworks 232
Importing a namespace to use a type 233
Relating C# keywords to .NET types 234
Sharing code with legacy platforms using .NET Standard 235
Creating a .NET Standard 2.0 class library 236
Publishing your applications for deployment 237
Creating a console application to publish 237
Understanding dotnet commands 238
Creating new projects 238
Managing projects 239
Publishing a self-contained app 239
Publishing a single-file app 240
Reducing the size of apps using app trimming 242
Decompiling assemblies 243
Packaging your libraries for NuGet distribution 246
Referencing a NuGet package 246
Fixing dependencies 247
Packaging a library for NuGet 247
Testing your package 250
Porting from .NET Framework to .NET 5 252
Could you port? 252
Should you port? 252
Differences between .NET Framework and .NET 5 253
Understanding the .NET Portability Analyzer 253
Using non-.NET Standard libraries 253
Practicing and exploring 255
Exercise 7.1 – Test your knowledge 255
Exercise 7.2 – Explore topics 256
Summary 256

Chapter 8: Working with Common .NET Types 257

Working with numbers 258
Working with big integers 258
Working with complex numbers 259
Working with text 260
Getting the length of a string 260
Getting the characters of a string 260
Splitting a string 261
Getting part of a string 261
Checking a string for content 262
Joining, formatting, and other string members 262
Building strings efficiently 264
Pattern matching with regular expressions 264
Checking for digits entered as text 264
Understanding the syntax of a regular expression 266
Examples of regular expressions 266
Splitting a complex comma-separated string 267
Regular expression performance improvements 268
Storing multiple objects in collections 269
Common features of all collections 270
Understanding collection choices 271
Lists 272
Dictionaries 272
Stacks 273
Queues 273
Sets 273
Working with lists 273
Working with dictionaries 275
Sorting collections 275
Using specialized collections 276
Using immutable collections 276
Working with spans, indexes, and ranges 277
Using memory efficiently using spans 277
Identifying positions with the Index type 278
Identifying ranges with the Range type 278
Using indexes and ranges 279
Working with network resources 280
Working with URIs, DNS, and IP addresses 280
Pinging a server 281
Working with types and attributes 282
Versioning of assemblies 283
Reading assembly metadata 284
Creating custom attributes 286
Doing more with reflection 288
Working with images 289
Internationalizing your code 290
Detecting and changing the current culture 291
Handling time zones 293
Practicing and exploring 293
Exercise 8.1 – Test your knowledge 293
Exercise 8.2 – Practice regular expressions 294
Exercise 8.3 – Practice writing extension methods 294
Exercise 8.4 – Explore topics 294
Summary 295

Chapter 9: Working with Files, Streams, and Serialization 297

Managing the filesystem 297
Handling cross-platform environments and filesystems 297
Managing drives 299
Managing directories 300
Managing files 303
Managing paths 304
Getting file information 305
Controlling how you work with files 307
Reading and writing with streams 307
Writing to text streams 309
Writing to XML streams 310
Disposing of file resources 312
Compressing streams 314
Compressing with the Brotli algorithm 316
High-performance streams using pipelines 318
Asynchronous streams 318
Encoding and decoding text 319
Encoding strings as byte arrays 319
Encoding and decoding text in files 322
Serializing object graphs 322
Serializing as XML 322
Generating compact XML 325
Deserializing XML files 326
Serializing with JSON 327
High-performance JSON processing 328
Practicing and exploring 330
Exercise 9.1 – Test your knowledge 330
Exercise 9.2 – Practice serializing as XML 331
Exercise 9.3 – Explore topics 332
Summary 332

Chapter 10: Protecting Your Data and Applications 333

Understanding the vocabulary of protection 334
Keys and key sizes 334
IVs and block sizes 335
Salts 335
Generating keys and IVs 336
Encrypting and decrypting data 336
Encrypting symmetrically with AES 337
Hashing data 341
Hashing with the commonly used SHA256 342
Signing data 345
Signing with SHA256 and RSA 346
Generating random numbers 349
Generating random numbers for games 349
Generating random numbers for cryptography 350
What's new in cryptography? 351
Authenticating and authorizing users 352
Implementing authentication and authorization 354
Protecting application functionality 357
Practicing and exploring 358
Exercise 10.1 – Test your knowledge 358
Exercise 10.2 – Practice protecting data with encryption and hashing 358
Exercise 10.3 – Practice protecting data with decryption 359
Exercise 10.4 – Explore topics 359
Summary 359

Chapter 11: Working with Databases Using Entity Framework Core 361

Understanding modern databases 361
Understanding legacy Entity Framework 362
Understanding Entity Framework Core 363
Using a sample relational database 363
Setting up SQLite for macOS 364
Setting up SQLite for Windows 365
Creating the Northwind sample database for SQLite 365
Managing the Northwind sample database with SQLiteStudio 366
Setting up EF Core 367
Choosing an EF Core database provider 367
Setting up the dotnet-ef tool 368
Connecting to the database 369
Defining EF Core models 369
EF Core conventions 370
EF Core annotation attributes 370
EF Core Fluent API 371
Understanding data seeding 372
Building an EF Core model 372
Defining the Category and Product entity classes 373
Defining the Northwind database context class 375
Scaffolding models using an existing database 377
Querying EF Core models 381
Filtering included entities 383
Filtering and sorting products 384
Getting the generated SQL 386
Logging EF Core 387
Logging with query tags 391
Pattern matching with Like 391
Defining global filters 392
Loading patterns with EF Core 393
Eager loading entities 393
Enabling lazy loading 394
Explicit loading entities 395
Manipulating data with EF Core 397
Inserting entities 397
Updating entities 399
Deleting entities 400
Pooling database contexts 401
Transactions 401
Defining an explicit transaction 402
Practicing and exploring 403
Exercise 11.1 – Test your knowledge 403
Exercise 11.2 – Practice exporting data using different serialization formats 403
Exercise 11.3 – Explore the EF Core documentation 404
Summary 404

Chapter 12: Querying and Manipulating Data Using LINQ 405

Writing LINQ queries 405
Extending sequences with the Enumerable class 406
Filtering entities with Where 407
Targeting a named method 409
Simplifying the code by removing the explicit delegate instantiation 410
Targeting a lambda expression 410
Sorting entities 410
Sorting by a single property using OrderBy 411
Sorting by a subsequent property using ThenBy 411
Filtering by type 412
Working with sets and bags using LINQ 413
Using LINQ with EF Core 415
Building an EF Core model 415
Filtering and sorting sequences 418
Projecting sequences into new types 419
Joining and grouping sequences 420
Aggregating sequences 424
Sweetening LINQ syntax with syntactic sugar 425
Using multiple threads with parallel LINQ 426
Creating an app that benefits from multiple threads 426
Using Windows 10 427
Using macOS 427
For all operating systems 428
Creating your own LINQ extension methods 429
Working with LINQ to XML 433
Generating XML using LINQ to XML 433
Reading XML using LINQ to XML 433
Practicing and exploring 434
Exercise 12.1 – Test your knowledge 435
Exercise 12.2 – Practice querying with LINQ 435
Exercise 12.3 – Explore topics 436
Summary 436

Chapter 13: Improving Performance and Scalability Using Multitasking 437

Understanding processes, threads, and tasks 437
Monitoring performance and resource usage 439
Evaluating the efficiency of types 439
Monitoring performance and memory use 440
Implementing the Recorder class 441
Measuring the efficiency of processing strings 443
Running tasks asynchronously 445
Running multiple actions synchronously 445
Running multiple actions asynchronously using tasks 446
Waiting for tasks 448
Continuing with another task 449
Nested and child tasks 450
Synchronizing access to shared resources 452
Accessing a resource from multiple threads 452
Applying a mutually exclusive lock to a resource 454
Understanding the lock statement and avoiding deadlocks 454
Synchronizing events 456
Making CPU operations atomic 457
Applying other types of synchronization 458
Understanding async and await 458
Improving responsiveness for console apps 459
Improving responsiveness for GUI apps 460
Improving scalability for web applications and web services 460
Common types that support multitasking 461
Using await in catch blocks 461
Working with async streams 461
Practicing and exploring 462
Exercise 13.1 – Test your knowledge 462
Exercise 13.2 – Explore topics 463
Summary 463

Chapter 14: Introducing Practical Applications of C# and .NET 465

Understanding app models for C# and .NET 465
Building websites using ASP.NET Core 466
Building websites using a web content management system 466
Understanding web applications 467
Building and consuming web services 468
Building intelligent apps 468
New features in ASP.NET Core 468
ASP.NET Core 1.0 468
ASP.NET Core 1.1 469
ASP.NET Core 2.0 469
ASP.NET Core 2.1 469
ASP.NET Core 2.2 470
ASP.NET Core 3.0 470
ASP.NET Core 3.1 471
Blazor WebAssembly 3.2 471
ASP.NET Core 5.0 471
Understanding SignalR 472
Understanding Blazor 474
JavaScript and friends 474
Silverlight – C# and .NET using a plugin 474
WebAssembly – a target for Blazor 474
Blazor on the server side or client side 475
Understanding the bonus chapters 475
Building cross-platform mobile and desktop apps 476
Building Windows desktop apps using legacy technologies 477
Building an entity data model for Northwind 478
Creating a class library for Northwind entity models 478
Generating entity models using dotnet-ef 478
Manually improving the class-to-table mapping 480
Creating a class library for a Northwind database context 482
Summary 484

Chapter 15: Building Websites Using ASP.NET Core Razor Pages 485

Understanding web development 485
Understanding HTTP 485
Client-side web development 489
Understanding ASP.NET Core 489
Classic ASP.NET versus modern ASP.NET Core 490
Creating an ASP.NET Core project 491
Testing and securing the website 493
Controlling the hosting environment 496
Enabling static and default files 497
Exploring Razor Pages 500
Enabling Razor Pages 500
Defining a Razor Page 501
Using shared layouts with Razor Pages 502
Using code-behind files with Razor Pages 505
Using Entity Framework Core with ASP.NET Core 507
Configure Entity Framework Core as a service 507
Manipulating data using Razor Pages 508
Enabling a model to insert entities 508
Defining a form to insert new suppliers 509
Using Razor class libraries 510
Creating a Razor class library 511
Disabling compact folders 511
Implementing the employees feature using EF Core 512
Implementing a partial view to show a single employee 514
Using and testing a Razor class library 515
Configuring services and the HTTP request pipeline 516
Registering services 518
Configuring the HTTP request pipeline 519
Simplest possible ASP.NET Core website project 523
Practicing and exploring 524
Exercise 15.1 – Test your knowledge 524
Exercise 15.2 – Practice building a data-driven web page 525
Exercise 15.3 – Practice building web pages for console apps 525
Exercise 15.4 – Explore topics 525
Summary 526

Chapter 16: Building Websites Using the Model-View-Controller Pattern 527

Setting up an ASP.NET Core MVC website 527
Creating and exploring an ASP.NET Core MVC website 528
Reviewing the ASP.NET Core MVC website 531
Reviewing the ASP.NET Core Identity database 532
Exploring an ASP.NET Core MVC website 533
Understanding ASP.NET Core MVC startup 533
Understanding the default MVC route 535
Understanding controllers and actions 536
Understanding the view search path convention 538
Unit testing MVC 539
Understanding filters 539
Using a filter to secure an action method 539
Using a filter to cache a response 540
Using a filter to define a custom route 540
Understanding entity and view models 541
Understanding views 543
Customizing an ASP.NET Core MVC website 546
Defining a custom style 546
Setting up the category images 546
Understanding Razor syntax 547
Defining a typed view 547
Reviewing the customized home page 550
Passing parameters using a route value 551
Understanding model binders 554
Validating the model 558
Understanding view helper methods 560
Querying a database and using display templates 561
Improving scalability using asynchronous tasks 564
Making controller action methods asynchronous 565
Using other project templates 566
Installing additional template packs 566
Practicing and exploring 567
Exercise 16.1 – Test your knowledge 567
Exercise 16.2 – Practice implementing MVC by implementing a category
detail page 568
Exercise 16.3 – Practice improving scalability by understanding and
implementing async action methods 568
Exercise 16.4 – Explore topics 568
Summary 569

Chapter 17: Building Websites Using a Content Management System 571

Understanding the benefits of a CMS 571
Understanding basic CMS features 572

Understanding enterprise CMS features 572
Understanding CMS platforms 573
Understanding Piranha CMS 573
Open source libraries and licensing 574
Creating a Piranha CMS website 574
Exploring a Piranha CMS website 576
Editing site and page content 577
Creating a new top-level page 580
Creating a new child page 582
Reviewing the blog archive 583
Commenting on posts and pages 585
Exploring authentication and authorization 586
Exploring configuration 588
Testing the new content 589
Understanding routing 589
Understanding media 591
Understanding the application service 592
Understanding content types 593
Understanding component types 593
Understanding standard fields 594
Customizing the rich text editor 594
Reviewing the Standard page type 595
Reviewing the Standard archive and post types 598
Understanding standard blocks 599
Reviewing component types and standard blocks 599
Defining components, content types, and templates 601
Creating custom regions 601
Creating an entity data model 603
Creating custom page types 604
Creating custom view models 605
Defining custom content templates for content types 606
Configuring startup and importing from a database 609
Learning how to create content using the project template 612
Testing the Northwind CMS website 613
Uploading images and creating the catalog root 613
Importing category and product content 614
Managing catalog content 616
Reviewing how Piranha stores content 617
Practicing and exploring 619
Exercise 17.1 – Test your knowledge 619
Exercise 17.2 – Practice defining a block type for rendering YouTube videos 619
Exercise 17.3 – Explore topics 620
Summary 620

Chapter 18: Building and Consuming Web Services 621

Building web services using the ASP.NET Core Web API 621
Understanding web service acronyms 622
Creating an ASP.NET Core Web API project 623
Reviewing the web service's functionality 626
Creating a web service for the Northwind database 627
Creating data repositories for entities 629
Implementing a Web API controller 632
Configuring the customers repository and Web API controller 634
Specifying problem details 638
Controlling XML serialization 639
Documenting and testing web services 640
Testing GET requests using a browser 640
Testing HTTP requests with the REST Client extension 641
Understanding Swagger 646
Testing requests with Swagger UI 647
Consuming services using HTTP clients 652
Understanding HttpClient 652
Configuring HTTP clients using HttpClientFactory 653
Getting customers as JSON in the controller 654
Enabling Cross-Origin Resource Sharing 656
Implementing advanced features 658
Implementing a Health Check API 658
Implementing Open API analyzers and conventions 659
Implementing transient fault handling 660
Understanding endpoint routing 660
Configuring endpoint routing 661
Adding security HTTP headers 663
Securing web services 664
Understanding other communication technologies 664
Understanding Windows Communication Foundation (WCF) 665
Understanding gRPC 665
Practicing and exploring 666
Exercise 18.1 – Test your knowledge 666
Exercise 18.2 – Practice creating and deleting customers with HttpClient 666
Exercise 18.3 – Explore topics 667
Summary 667

Chapter 19: Building Intelligent Apps Using Machine Learning 669

Understanding machine learning 669
Understanding the machine learning lifecycle 670
Understanding datasets for training and testing 671
Understanding machine learning tasks 672
Understanding Microsoft Azure Machine Learning 672
Understanding ML.NET 673
Understanding Infer.NET 673
Understanding ML.NET learning pipelines 674
Understanding model training concepts 675
Understanding missing values and key types 676
Understanding features and labels 676
Making product recommendations 676
Problem analysis 677
Data gathering and processing 678
Creating the NorthwindML website project 679
Creating the data and view models 680
Implementing the controller 682
Training the recommendation models 685
Implementing a shopping cart with recommendations 687
Testing the product recommendations website 692
Practicing and exploring 695
Exercise 19.1 – Test your knowledge 695
Exercise 19.2 – Practice with samples 695
Exercise 19.3 – Explore topics 696
Summary 697

Chapter 20: Building Web User Interfaces Using Blazor 699

Understanding Blazor 699
Understanding Blazor hosting models 700
Understanding Blazor components 700
What is the deal with Blazor and Razor? 701
Comparing Blazor project templates 701
Reviewing the Blazor Server project template 701
Understanding CSS isolation 706
Running the Blazor Server project template 707
Reviewing the Blazor WebAssembly project template 708
Building components using Blazor Server 711
Defining and testing a simple component 711
Getting entities into a component 712
Abstracting a service for a Blazor component 715
Using Blazor forms 717
Defining forms using the EditForm component 718
Navigating Blazor routes 718
Building and using a customer form component 719
Building components using Blazor WebAssembly 724
Configuring the server for Blazor WebAssembly 725
Configuring the client for Blazor WebAssembly 728
Exploring Progressive Web App support 732
Practicing and exploring 734
Exercise 20.1 – Test your knowledge 734
Exercise 20.2 – Practice creating a component 734
Exercise 20.3 – Explore topics 735
Summary 735

Chapter 21: Building Cross-Platform Mobile Apps 737

Understanding XAML 738
Simplifying code using XAML 738
Choosing common controls 739
Understanding markup extensions 739
Understanding Xamarin and Xamarin.Forms 740
How Xamarin.Forms extends Xamarin 740
Development tools for mobile first, cloud first 740
Mobile platform market share 741
Understanding additional functionality 741
Understanding the INotificationPropertyChanged interface 742
Understanding dependency services 742
Understanding Xamarin.Forms user interface components 743
Understanding the ContentPage view 743
Understanding the Entry and Editor controls 744
Understanding the ListView control 744
Building mobile apps using Xamarin.Forms 745
Adding Android SDKs 745
Creating a Xamarin.Forms solution 745
Creating an entity model with two-way data binding 747
Creating a component for dialing phone numbers 751
Creating views for the customers list and customer details 754
Implementing the customer list view 755
Implementing the customer detail view 758
Setting the main page for the mobile app 760
Testing the mobile app 761
Consuming a web service from a mobile app 763
Configuring the web service to allow insecure requests 763
Configuring the iOS app to allow insecure connections 764
Configuring the Android app to allow insecure connections 765
Adding NuGet packages for consuming a web service 766
Getting customers from the web service 766
Practicing and exploring 768
Exercise 21.1 – Test your knowledge 768
Exercise 21.2 – Explore topics 769
Summary 769
Epilogue 770
Index 771