C# 7 and .NET Core: Modern Cross-Platform Development E-Book

Mark J. Price

• Herausgeber: Packt Publishing
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 492

Veröffentlichungsjahr: 2017

Beschreibung

If you want to build powerful cross-platform applications with C# 7 and .NET Core, then this book is for you.
First, we’ll run you through the basics of C#, as well as object-oriented programming, before taking a quick tour through the latest features of C# 7 such as tuples, pattern matching, out variables, and so on.
After quickly taking you through C# and how .NET works, we’ll dive into the .NET Standard 1.6 class libraries, covering topics such as performance, monitoring, debugging, serialization and encryption.
The final section will demonstrate the major types of application that you can build and deploy cross-device and cross-platform. In this section, we’ll cover Universal Windows Platform (UWP) apps, web applications, mobile apps, and web services. Lastly, we’ll look at how you can package and deploy your applications so that they can be hosted on all of today’s most popular platforms, including Linux and Docker.
By the end of the book, you’ll be armed with all the knowledge you need to build modern, cross-platform applications using C# and .NET Core.

Leseprobe

Table of Contents

C# 7 and .NET Core: Modern Cross-Platform Development - Second Edition

Credits

About the Author

About the Reviewer

www.PacktPub.com

Why subscribe?

Customer Feedback

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Hello, C#! Welcome, .NET Core!

Choosing your development environment

Using alternative C# IDEs

Deploying cross-platform

Installing Microsoft Visual Studio 2017 for Windows

Choosing workloads

Choosing additional components

Signing in to Visual Studio 2017

Choosing your settings

Reviewing Visual Studio's user interface

Installing Microsoft Visual Studio Code for Windows, macOS, or Linux

Installing Microsoft Visual Studio Code for macOS

Installing .NET Core for macOS

Installing Homebrew

Installing OpenSSL

Installing .NET Core SDK

Installing the Visual Studio Code extension for C#

Understanding .NET

Understanding .NET Framework

Understanding the Mono and Xamarin projects

Understanding .NET Core

Streamlining .NET

Understanding .NET Standard

.NET used in this book

Understanding .NET Native

Comparing .NET technologies

Writing and compiling code using the .NET Core CLI tool

Writing code using a simple text editor

If you are using Windows Notepad

If you are using macOS TextEdit

Compiling code using the .NET Core CLI tool

Restoring packages and running the application

Fixing compiler errors

Understanding Intermediate Language

Writing and compiling code using Microsoft Visual Studio 2017

Writing code using Microsoft Visual Studio 2017

Coding with Visual Studio's editor

Compiling code using Visual Studio 2017

Fixing mistakes with the error list

Adding existing projects to Visual Studio 2017

Autoformatting code

Experimenting with C# Interactive

Other useful windows

Writing and compiling code using Microsoft Visual Studio Code

Writing code using Visual Studio Code

Compiling code using Visual Studio Code

Managing source code with GitHub

Using Git with Visual Studio 2017

Using the Team Explorer window

Cloning a GitHub repository

Managing a GitHub repository

Using Git with Visual Studio Code

Configuring Git at the command line

Managing Git with Visual Studio Code

Practicing and exploring

Exercise 1.1 - test your knowledge

Exercise 1.2 - practice coding anywhere

Exercise 1.3 - explore topics

Summary

2. Speaking C#

Understanding C# basics

Using Visual Studio 2017

Using Visual Studio Code on macOS, Linux, or Windows

C# grammar

Statements

Comments

Blocks

C# vocabulary

C# keywords

Writing the code

Verbs are methods

Nouns are types, fields, and variables

Counting types and methods

Building and running with Visual Studio 2017

Building and running with Visual Studio Code

Declaring variables

Naming variables

Literal values

Storing text

Storing numbers

Storing whole numbers

C# 7 improvements

Storing real numbers

Using Visual Studio 2017

Using Visual Studio Code

Writing code to explore numbers

Comparing double and decimal

Storing Booleans

The object type

The dynamic type

Local variables

Inferring the type of a local variable

Making a value type nullable

Checking for null

Storing multiple values in an array

Building console applications

Displaying output to the user

Getting input from the user

Importing a namespace

Simplifying the usage of the console

Reading arguments and working with arrays

Passing arguments with Visual Studio 2017

Passing arguments with Visual Studio Code

Viewing the output

Enumerating arguments

Running on Windows

Running on macOS

Handling platforms that do not support an API

Operating on variables

Experimenting with unary operators

Experimenting with arithmetic operators

Comparison and Boolean operators

Practicing and exploring

Exercise 2.1 - test your knowledge

Exercise 2.2 - practice number sizes and ranges

Exercise 2.3 - explore topics

Summary

3. Controlling the Flow, Converting Types, and Handling Exceptions

Selection statements

Using Visual Studio 2017

Using Visual Studio Code on macOS, Linux, or Windows

The if statement

Pattern matching with the if statement

The switch statement

Pattern matching with the switch statement

Iteration statements

The while statement

The do statement

The for statement

The foreach statement

How does the foreach statement work?

Casting and converting between types

Casting from numbers to numbers

Casting explicitly

Using the convert type

Rounding numbers

Converting from any type to a string

Parsing from strings to numbers or dates and times

Handling exceptions

The try statement

Catching all exceptions

Catching specific exceptions

The finally statement

Simplifying disposal with the using statement

Checking for overflow

The checked statement

The unchecked statement

Looking for help

Microsoft Docs and MSDN

Go to definition

StackOverflow

Google

Subscribing to blogs

Design patterns

Singleton pattern

Practice and explore

Exercise 3.1 - test your knowledge

Exercise 3.2 - explore loops and overflow

Exercise 3.3 - practice loops and operators

Exercise 3.4 - practice exception handling

Exercise 3.5 - explore topics

Summary

4. Using .NET Standard Types

Using assemblies and namespaces

Comparing .NET Framework with .NET Core

Base Class Libraries and CoreFX

Assemblies, NuGet packages, and platforms

Namespaces

Referencing a dependent assembly

Browsing assemblies with Visual Studio 2017

Understanding .NET Core project files

Relating assemblies and namespaces

Importing a namespace

Relating C# keywords to .NET types

Storing and manipulating text

Getting the length of a string

Getting the characters of a string

Splitting a string

Getting part of a string

Checking a string for content

Other string members

Building strings efficiently

Pattern matching with regular expressions

The syntax of a regular expression

Examples of regular expressions

Storing data with collections

Understanding collections

Lists

Dictionaries

Stacks

Queues

Sets

Working with lists

Working with dictionaries

Sorting collections

Using specialized collections

Internationalizing an application

Globalizing an application

Practicing and exploring

Exercise 4.1 - test your knowledge

Exercise 4.2 - practice regular expressions

Exercise 4.3 - explore topics

Summary

5. Debugging, Monitoring, and Testing

Debugging tools

Debugging an application

Setting a breakpoint

The debugging toolbar

Debugging windows

Stepping through code

Customizing breakpoints

Monitoring performance and resource usage

Evaluating the efficiency of types

Monitoring performance and memory use

Measuring the efficiency of processing strings

Unit testing an application

Creating a class library that needs testing with Visual Studio 2017

Creating a unit test project with Visual Studio 2017

Creating a class library that needs testing with Visual Studio Code

Writing unit tests

Running unit tests with Visual Studio 2017

Running unit tests with Visual Studio Code

Practicing and exploring

Exercise 5.1 - test your knowledge

Exercise 5.2 - practice debugging and unit testing

Exercise 5.3 - explore topics

Summary

6. Building Your Own Types with Object-Oriented Programming

Talking about OOP

Building class libraries

Creating a class library with Visual Studio 2017

Creating a class library with Visual Studio Code

Defining a class

Instantiating a class

Referencing an assembly using Visual Studio 2017

Referencing an assembly using Visual Studio Code

Importing a namespace

Managing multiple projects with Visual Studio Code

Inheriting from System.Object

Storing data with fields

Defining fields

Understanding access modifiers

Storing a value using the enum keyword

Storing multiple values using collections

Making a field static

Making a field constant

Making a field read-only

Initializing fields with constructors

Writing and calling methods

Combining multiple values with tuples

Referencing the System.ValueTuple package with Visual Studio 2017

Referencing the System.ValueTuple package with Visual Studio Code

Defining methods with tuples

Naming the fields of a tuple

Deconstructing tuples

Defining and passing parameters to methods

Overloading methods

Optional parameters and named arguments

Controlling how parameters are passed

Splitting classes using partial

Controlling access with properties and indexers

Defining read-only properties

Defining settable properties

Defining indexers

Practicing and exploring

Exercise 6.1 - test your knowledge

Exercise 6.2 - practice writing mathematical methods

Exercise 6.3 - explore topics

Summary

7. Implementing Interfaces and Inheriting Classes

Setting up a class library and console application

Using Visual Studio 2017

Using Visual Studio Code

Defining the classes

Simplifying methods with operators

Implementing some functionality with a method

Implementing some functionality with an operator

Defining local functions

Raising and handling events

Calling methods using delegates

Defining events

Implementing interfaces

Common interfaces

Comparing objects when sorting

Defining a separate comparer

Managing memory with reference and value types

Defining a struct type

Releasing unmanaged resources

Ensuring that dispose is called

Inheriting from classes

Extending classes

Hiding members

Overriding members

Preventing inheritance and overriding

Polymorphism

Casting within inheritance hierarchies

Implicit casting

Explicit casting

Handling casting exceptions

Inheriting and extending .NET types

Inheriting from an exception

Extending types when you can't inherit

Using static methods to reuse functionality

Using extension methods to reuse functionality

Practice and explore

Exercise 7.1 - test your knowledge

Exercise 7.2 - practice creating an inheritance hierarchy

Exercise 7.3 - explore topics

Summary

8. Working with Databases Using the Entity Framework Core

Relational Database Management Systems

Using a sample database

Using Microsoft SQL Server on Windows

Connecting to Microsoft SQL Server LocalDb

Creating the Northwind sample database

Managing the Northwind sample database

Using SQLite on macOS and mobile platforms

Running a script for SQLite

Choosing a .NET data provider

Connecting to the database

Setting up Entity Framework Core

Using Visual Studio 2017

Using Visual Studio Code

Entity Framework Core models

EF Core conventions

EF Core annotation attributes

EF Core Fluent API

Building an EF Core Model

Querying an EF Core model

Logging EF Core

Loading patterns with EF Core

Eager and lazy loading entities

Explicit loading entities

Manipulating data with EF Core

Inserting entities

Updating entities

Deleting entities

Transactions

Defining an explicit transaction

Practicing and exploring

Exercise 8.1 - test your knowledge

Exercise 8.2 - explore the EF Core documentation

Summary

9. Querying and Manipulating Data with LINQ

Writing LINQ queries

Extending sequences with the enumerable class

Filtering entities with Where

Targeting a named method

Simplifying the code by removing the explicit delegate instantiation

Targeting a lambda expression

Sorting entities with OrderBy

Sorting by multiple properties with the ThenBy method

Working with sets

Projecting entities with Select

Building an EF Core model

Joining and grouping

Sweetening the syntax with syntactic sugar

Using multiple threads with parallel LINQ

Creating your own LINQ extension methods

Working with LINQ to XML

Generating XML using LINQ to XML

Reading XML by using LINQ to XML

Practicing and exploring

Exercise 9.1 - test your knowledge

Exercise 9.2 - practice querying with LINQ

Exercise 9.3 - explore topics

Summary

10. Working with Files, Streams, and Serialization

Managing the filesystem

Managing directories

Managing files

Managing paths

Getting file information

Reading and writing with streams

Writing to text and XML streams

Compressing streams

Encoding text

Encoding strings as byte arrays

Encoding and decoding text in files

Serializing object graphs

Serializing with XML

Deserializing with XML

Customizing the XML

Serializing with JSON

Serializing with other formats

Practice and explore

Exercise 10.1 - test your knowledge

Exercise 10.2 - practice serializing as XML

Exercise 10.3 - explore serialization formats

Exercise 10.4 - explore topics

Summary

11. Protecting Your Data

Understanding the vocabulary of protection

Keys and key sizes

IVs and block sizes

Salts

Generating keys and IVs

Encrypting and decrypting data

Encrypting symmetrically with AES

Using Visual Studio 2017

Using Visual Studio Code

Creating the Protector class

Hashing data

Hashing with SHA256

Signing data

Signing with SHA256 and RSA

Practicing and exploring

Exercise 11.1 - test your knowledge

Exercise 11.2 - practice protecting data with encryption and hashing

Exercise 11.3 - practice protecting data with decryption

Exercise 11.4 - explore topics

Summary

12. Improving Performance and Scalability with Multitasking

Understanding processes, threads, and tasks

Running tasks asynchronously

Running multiple actions synchronously

Running multiple actions asynchronously using tasks

Waiting for tasks

Continuing with another task

Nested and child tasks

Synchronizing access to shared resources

Accessing a resource from multiple threads

Applying a mutually exclusive lock to a resource

Understanding the lock statement

Making operations atomic

Applying other types of synchronization

Implementing multitasking for a GUI

Creating a GUI that blocks

Creating a GUI that doesn't block

Other types with Async methods

await in catch blocks

Improving scalability for client-server applications

Practicing and exploring

Exercise 12.1 - test your knowledge

Exercise 12.2 - explore topics

Summary

13. Building Universal Windows Platform Apps Using XAML

Understanding Universal Windows Platform

Adapting your app's layout

Taking advantage of unique device capabilities

Understanding XAML

Simplifying code using XAML

Choosing common controls

Creating an app for Universal Windows Platform

Using resources and templates

Sharing resources

Replacing a control template

Data binding

Binding to elements

Binding to data

Animating with storyboards

Testing in emulators

Practicing and exploring

Exercise 13.1 - test your knowledge

Exercise 13.2 - practice building a universal tip calculator

Exercise 13.3 - explore topics

Summary

14. Building Web Applications Using ASP.NET Core MVC

Understanding ASP.NET Core

Classic ASP.NET versus modern ASP.NET Core

Client-side web development

Understanding HTTP

Creating an ASP.NET Core project with Visual Studio 2017

Performing database migrations

Reviewing authentication with ASP.NET Identity

Creating an ASP.NET Core project with Visual Studio Code

Managing client-side packages with Bower

Exploring an ASP.NET Core MVC web application

ASP.NET Core startup

Understanding the default route

ASP.NET Core MVC controllers

ASP.NET Core MVC models

Create Entity models for Northwind

Configure Entity Framework Core as a service

Create view models for requests

Fetch the model in the controller

ASP.NET Core MVC views

Rendering the Home controller's views

Sharing layouts between views

Defining custom styles

Defining a typed view

Taking ASP.NET Core MVC further

Passing parameters using a route value

Passing parameters using a query string

Annotating models

Practicing and exploring

Exercise 14.1 - test your knowledge

Exercise 14.2 - practice building a data-driven web application

Exercise 14.3 - explore topics

Summary

15. Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API

Understanding Xamarin.Forms

How Xamarin.Forms extends Xamarin

Mobile first, cloud first

Installing Xcode

Installing Visual Studio for Mac

Building services using ASP.NET Core Web API and Visual Studio Code

Creating an ASP.NET Core Web API project

Creating a web service for the Northwind database

Creating the Northwind database

Referencing the EF Core NuGet packages

Creating the entity model and database context

Creating the data repository

Configuring and registering the data repository

Set the database connection string

Creating the Web API controller

Testing the web service

Testing GET requests with any browser

Testing POST, PUT, DELETE, and other requests with Postman

Building mobile apps using Xamarin.Forms and Visual Studio for Mac

Creating a Xamarin.Forms project

Creating a model

Creating an interface for dialing phone numbers and implement for iOS and Android

Creating views for the customers list and customer details

Test the mobile app with iOS

Adding NuGet packages for calling a REST service

Getting customers from the service

Practicing and exploring

Exercise 15.1 - test your knowledge

Exercise 15.2 - explore topics

Summary

16. Packaging and Deploying Your Code Cross-Platform

Porting to .NET Core

Could you port?

Should you port?

Differences between .NET Framework and .NET Core

Understanding the .NET Portability Analyzer

Sharing code cross-platform with .NET Standard class libraries

Creating a .NET Standard class library

Using Visual Studio 2017

Using Visual Studio Code on macOS

Understanding NuGet packages

Referencing packages

Understanding metapackages

Understanding Frameworks

Fixing dependencies

Switching to a different .NET Standard

Publishing your applications

Creating a console application to publish

Publishing with Visual Studio 2017

Publishing with Visual Studio Code

Deploying to the cloud

Creating an ASP.NET Core MVC web application to publish

Register an Azure account

Create an Azure web app

Publishing an ASP.NET web application to the web app

Developing on and for Linux

Practicing and exploring

Exercise 16.1 - test your knowledge

Exercise 16.2 - explore topics

Summary

A. Answers to the Test Your Knowledge Questions

Chapter 1 - Hello, C#! Welcome, .NET Core!

Chapter 2 - Speaking C#

Chapter 3 - Controlling the Flow, Converting Types, and Handling Exceptions

Chapter 4 - Using .NET Standard Types

Chapter 5 - Debugging, Monitoring, and Testing

Chapter 6 - Building Your Own Types with Object-Oriented Programming

Chapter 7 - Implementing Interfaces and Inheriting Classes

Chapter 8 - Working with Databases Using Entity Framework Core

Chapter 9 - Querying and Manipulating Data with LINQ

Chapter 10 - Working with Files, Streams, and Serialization

Chapter 11 - Protecting Your Data

Chapter 12 - Improving Performance and Scalability with Multitasking

Chapter 13 - Building Universal Windows Platform Apps Using XAML

Chapter 14 - Building Web Applications Using ASP.NET Core MVC

Chapter 15 - Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API

Chapter 16 - Packaging and Deploying Your Code Cross-Platform

C# 7 and .NET Core: Modern Cross-Platform Development - Second Edition

C# 7 and .NET Core: Modern Cross-Platform Development - Second Edition

Copyright © 2017 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: March 2016

Second edition: March 2017

Production reference: 1210317

Published by Packt Publishing Ltd.

Livery Place

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ISBN 978-1-78712-955-9

www.packtpub.com

Credits

Author

Mark J. Price

Copy Editor

Zainab Bootwala

Reviewer

Fabio Claudio Ferracchiati

Project Coordinator

Izzat Contractor

Commissioning Editor

Aaron Lazar

Proofreader

Safis Editing

Acquisition Editor

Nitin Dasan

Indexer

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Content Development Editor

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Graphics

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Technical Editors

Sunith Shetty

Abhishek Sharma

Production Coordinator

Nilesh Mohite

About the Author

Mark J. Price is a Microsoft Certified Trainer (MCT) and Microsoft Specialist: Programming in C# and Architecting Microsoft Azure Solutions, with more than 20 years of educational and programming experience.

Since 1993, Mark has passed more than 80 Microsoft programming exams and specializes in preparing others to pass them too. His students range from professionals with decades of experience to 16 year old apprentices with none. He successfully guides all of them by combining educational skills with real-world experience in consulting and developing systems for enterprises worldwide.

Between 2001 and 2003, Mark was employed full-time to write official courseware for Microsoft in Redmond, USA. His team wrote the first training courses for C# while it was still an early alpha version. While with Microsoft, he taught "train-the-trainer" classes to get other MCTs up-to-speed on C# and .NET.

Currently, Mark creates and delivers training courses for Episerver's Digital Experience Cloud, the best .NET CMS for Digital Marketing and E-commerce.

In 2010, Mark studied for a Postgraduate Certificate in Education (PGCE). He taught GCSE and A-Level mathematics in two London secondary schools. He holds a Computer Science BSc. Hons. Degree from the University of Bristol, UK.

Thank you to my parents, Pamela and Ian, for raising me to be polite, hardworking, and curious about the world. Thank you to my sisters, Emily and Juliet, for loving me despite being their awkward older brother. Thank you to my friends and colleagues who inspire me technically and creatively. Lastly, thanks to all the students I have taught over the years for motivating me to be the best teacher that I can be.

About the Reviewer

Fabio Claudio Ferracchiati is a senior consultant and a senior analyst/developer using Microsoft technologies. He works for React Consulting (www.reactconsulting.it). He is a Microsoft Certified Solution Developer for .NET, a Microsoft Certified Application Developer for .NET, a Microsoft Certified Professional, and a prolific author and technical reviewer. Over the past ten years, he's written articles for Italian and international magazines and co-authored more than ten books on a variety of computer topics.

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Preface

There are C# books that are thousands of pages long that aim to be comprehensive references to the C# programming language and the .NET Framework.

This book is different. It is concise and aims to be a fast-paced read that is packed with hands-on walkthroughs. I wrote this book to be the best step-by-step guide to modern cross-platform C# proven practices using .NET Core.

I will point out the cool corners and gotchas of C# so you can impress colleagues and employers and get productive fast. Rather than slowing down and boring some readers by explaining every little thing, I will assume that if a term I use is new to you, then you will know how to Google it.

At the end of each chapter is a section titled Practice and explore, in which you will complete hands-on practical exercises and explore topics deeper on your own with a little nudge in the right direction from me.

You can download solutions for the exercises from the following GitHub repository. I will provide instructions on how to do this using Visual Studio 2017 and Visual Studio Code at the end of Chapter 1, Hello, C#! Welcome, .NET Core!

https://github.com/markjprice/cs7dotnetcore.

What this book covers

Chapter 1, Hello, C#! Welcome, .NET Core!, is about setting up your development environment and using various tools to create the simplest application possible with C#. You will learn how to write and compile code using Visual Studio 2017 on Windows, or Visual Studio Code on macOS, Linux, or Windows. You will learn about the different .NET technologies: .NET Framework, .NET Core, .NET Standard, and .NET Native.

Chapter 2, Speaking C#, is about the C# language---the grammar and vocabulary that you will use every day to write the source code for your applications. In particular, you will learn how to declare and work with variables of different types.

Chapter 3, Controlling Flow, Converting Types, and Handling Exceptions, is about writing code that makes decisions, repeats a block of statements, converts between types, and handles errors. You will also learn the best places to look for help.

Chapter 4, Using .NET Standard Types, is about commonly used .NET Core types that are part of .NET Standard and how they are related to C#. You will learn about the .NET Standard class library assemblies and the NuGet packages of types that allow your applications to connect existing components to perform common practical tasks, such as manipulating text, storing items in collections, and implementing internationalization.

Chapter 5, Debugging, Monitoring, and Testing, is about debugging tools, monitoring, diagnosing problems, and testing your code to remove bugs and ensuring high performance, stability, and reliability.

Chapter 6, Building Your Own Types with Object-Oriented Programming, is about all the different categories of members that a type can have, including fields to store data and methods to perform actions. You will use OOP concepts, such as aggregation and encapsulation. You will learn about the C# 7 language features such as tuple syntax support and out variables.

Chapter 7, Implementing Interfaces and Inheriting Classes, is about deriving new types from existing ones using object-oriented programming (OOP). You will learn how to define operators and C# 7 local functions, delegates and events, how to implement interfaces about base and derived classes, how to override a type member, how to use polymorphism, how to create extension methods, and how to cast between classes in an inheritance hierarchy.

Chapter 8, Working with Databases Using Entity Framework Core, is about reading and writing to databases, such as Microsoft SQL Server and SQLite, using the object-relational mapping technology known as the Entity Framework Core.

Chapter 9, Querying and Manipulating Data with LINQ, is about Language INtegrated Query (LINQ)---language extensions that add the ability to work with sequences of items and filter, sort, and project them into different outputs.

Chapter 10, Working with Files, Streams, and Serialization, is about managing the filesystem, reading and writing to files and streams, text encoding, and serialization.

Chapter 11, Protecting Your Data, is about protecting your data from being viewed by malicious users using encryption and from being manipulated or corrupted using hashing and signing.

Chapter 12, Improving Performance and Scalability with Multitasking, is about allowing multiple actions to occur at the same time to improve performance, scalability, and user productivity.

Chapter 13, Building Universal Windows Platform Apps Using XAML, is about learning the basics of XAML that can be used to define the user interface for a graphical app for the Universal Windows Platform (UWP). This app can then run on Windows 10, Windows 10 Mobile, Xbox One, and even HoloLens.

Chapter 14, Building Web Applications Using ASP.NET Core MVC, is about learning the basics of building web applications with a modern HTTP architecture on the server side using ASP.NET Core MVC. You will learn about the startup configuration, authentication, routes, models, views, and controllers that make up ASP.NET Core MVC.

Chapter 15, Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API, is about learning the basics of how to take C# mobile by building a cross-platform mobile app for iOS and Android that calls a service built on ASP.NET Core Web API. The client-side mobile app will be created with Visual Studio for Mac and the server-side Web API service will be created with Visual Studio Code, both running on macOS.

Chapter 16, Packaging and Deploying Your Code Cross-Platform, is about publishing your apps and libraries, creating and distributing NuGet packages, and deploying your code cross-platform and to the cloud.

Appendix A, Answers to the Test Your Knowledge Questions, has the answers to the test questions at the end of each chapter.

What you need for this book

You can develop and deploy C# on many platforms, including Windows, macOS, and many varieties of Linux. For the best programming experience, and to reach the most platforms, I recommend that you learn the basics of all members of the Visual Studio family: Visual Studio 2017, Visual Studio Code, and Visual Studio for Mac.

My recommendation for the operating system and development tool combinations is as follows:

Windows 10 for Visual Studio 2017macOS for Visual Studio for MacmacOS for Visual Studio Code

The best version of Windows to use is Microsoft Windows 10 because you will need this version to create Universal Windows Platform apps in Chapter 13, Building Universal Windows Platform Apps Using XAML. Earlier versions of Windows, such as 7 or 8.1 will work for all other chapters.

Who this book is for

If you have heard that C# is a popular general-purpose cross-platform programming language used to create everything, ranging from business applications, web sites, and services, to games for mobile devices, Xbox One, and the Windows 10 desktop to tablet and phone platforms, then this book is for you.

If you have heard that .NET Core is Microsoft's bet on a cross-platform .NET future, optimized for server-side web development in the cloud, and client-side mobile development with Xamarin, combined with a cross-platform development tool in Visual Studio Code, then this book is for you.

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

This chapter is about setting up your development environment; understanding the similarities and differences between .NET Core, .NET Framework, .NET Standard, and .NET Native; and using various tools to create the simplest application possible with C# 7 and .NET Core.

Most people learn complex topics by imitation and repetition rather than reading a detailed explanation of theory. So, I will not explain every keyword and step. The idea is to get you to write some code, build an application, and see it run. You don't need to know the details of how it all works yet.

In the words of Samuel Johnson, author of the English dictionary of 1755, I have likely committed "a few wild blunders, and risible absurdities, from which no work of such multiplicity is free. "I take sole responsibility for these and hope you appreciate the challenge of my attempt to "lash the wind" by writing this book about .NET Core and its command-line tooling during its rocky birth during 2016 and 2017.

This chapter covers the following topics:

Choosing your development environmentInstalling Microsoft Visual Studio 2017 for WindowsInstalling Microsoft Visual Studio Code for Windows, macOS, or LinuxUnderstanding .NETWriting and compiling code using the .NET Core CLI toolWriting and compiling code using Microsoft Visual Studio 2017Writing and compiling code using Microsoft Visual Studio CodeManaging source code with GitHub

Choosing your development environment

Before you start programming, you will need to choose an Interactive Development Environment (IDE) that includes a code editor for C#.

The most mature and full-featured IDE to choose is Microsoft Visual Studio 2017, but it only runs on the Windows operating system.

The most modern and lightweight IDE to choose, and the only one from Microsoft that is cross-platform, is Microsoft Visual Studio Code, and it will run on all common operating systems, including Windows, macOS, and many varieties of Linux, such as Red Hat Enterprise Linux (RHEL) and Ubuntu.

Note

To help you decide if Visual Studio Code is right for you, I recommend that you watch the following video, Beginner's Guide to VS Code: Up and Running in Ten Minutes: https://channel9.msdn.com/Blogs/raw-tech/Beginners-Guide-to-VS-Code

To create apps for iOS (iPhone and iPad), tvOS, macOS, and watchOS, you must have OS X or macOS, and Xcode. Although you can use Visual Studio 2017 with its Xamarin extensions to write a cross-platform mobile app, you still need OS X or macOS, and Xcode to compile it. So, in Chapter 15, Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API, I will show you how to use Visual Studio for Mac running on macOS to create a Xamarin cross-platform mobile app for iOS and Android that calls a web service hosted on ASP.NET Core.

The following table shows which IDE and operating systems can or must be used for each of the chapters in this book:

Tip

Good Practice

If you have the option, then I recommend you try all the coding exercises with both Visual Studio 2017 on Windows, and Visual Studio Code on macOS, Linux, or Windows. It will be good for you to get experience with C# 7 and .NET Core on a variety of operating systems and development tools.

To write the second edition of this book, I used the following listed software, as you can see in the following screenshot:

Visual Studio Code version 1.10.2 and Visual Studio for Mac Preview 4, on macOS Sierra version 10.12.3Visual Studio 2017 on Windows 10 (in a virtual machine)Visual Studio Code on Red Hat Enterprise Linux (in a virtual machine)

Using alternative C# IDEs

There are alternative IDEs for C#, for example, MonoDevelop and JetBrains Rider. You can install either of these two IDEs with the help of the following URLs:

For MonoDevelop IDE, visit http://www.monodevelop.com/For JetBrains Rider, visit https://www.jetbrains.com/rider/

Cloud9 is a web browser-based IDE, so it's even more cross-platform than the others. It is growing in popularity. Here is the link:https://c9.io/web/sign-up/free.

Deploying cross-platform

Your choice of IDE and operating system for development does not limit where your code gets deployed. .NET Core currently supports the following platforms for deployment:

Windows 7 SP1, or laterWindows Server 2008 R2 SP1, or laterOS X El Capitan (version 10.11) and macOS Sierra (version 10.12)Red Hat Enterprise Linux 7.2Ubuntu 14.04 LTS, 16.04 LTSLinux Mint 17Debian 8.2CentOS 7.1Oracle Linux 7.1Docker

Note

Docker and Linux OSes are popular server host platforms because they are relatively lightweight and more cost-effectively scalable when compared to operating system platforms that are more for end users, such as Windows and macOS.

In the next section, you will install Microsoft Visual Studio 2017 for Windows. If you prefer to use Microsoft Visual Studio Code, jump ahead to the section titled, Installing Microsoft Visual Studio Code for Windows, macOS, or Linux.

Installing Microsoft Visual Studio 2017 for Windows

You can use Windows 7 SP1 or later to complete most of the chapters in this book, but you will have a better experience if you use Windows 10.

Since October 2014, Microsoft has made a professional-quality edition of Visual Studio available to everyone for free. It is called the Community Edition.

Note

Microsoft has combined all its free developer offerings in a program called Visual Studio Dev Essentials. This includes the Community Edition, the free level of Visual Studio Team Services, Azure credits for test and development, and free training from Pluralsight, Wintellect, and Xamarin.

Download and install Microsoft Visual Studio 2017 from the following link:https://www.visualstudio.com/downloads/

Choosing workloads

On the Workloads tab, choose the following, as partially shown in the following screenshot:

Universal Windows Platform development.NET desktop developmentASP.NET and web developmentAzure developmentMobile development with .NET.NET Core cross-platform development

Choosing additional components

On the Individual components tab, choose the following additional components, as shown in the following screenshot:

Class DesignerPowerShell toolsGit for WindowsGitHub extension for Visual Studio

Click Install, and wait for the installer to acquire the selected software, and install it, as shown in the following screenshot:

When the installation is complete, click Launch.

Note

While you wait for Visual Studio 2017 to install, you can jump ahead to the Understanding .NET section in this chapter.

Signing in to Visual Studio 2017

The first time that you run Visual Studio 2017, you will be prompted to sign in. If you have a Microsoft account, for example, a Hotmail, MSN, Live, or Outlook e-mail address, you can use that account. If you don't, then register for a new one at the following link: https://signup.live.com/.

Choosing your settings

When starting Visual Studio 2017 for the first time, you will be prompted to configure your environment. For Development Settings, choose Visual C#. For color theme, I chose Blue, but you can choose whatever suits you, as shown in the following screenshot:

Reviewing Visual Studio's user interface

You will see the Microsoft Visual Studio user interface with the  Start Page open in the central area. Like most Windows desktop applications, Visual Studio has a menu bar, a toolbar for common commands, and a status bar at the bottom. On the right is the Solution Explorer that will list your open projects:

Note

To have quick access to Visual Studio in the future, right-click on its entry in the Windows taskbar and select Pin to taskbar.

Installing Microsoft Visual Studio Code for Windows, macOS, or Linux

Between June 2015 and March 2017, Microsoft released a new version of Visual Studio Code every month (except for December 2016 because even Microsoft employees deserve a break for Christmas). Visual Studio Code has rapidly improved, and has surprised Microsoft with its popularity. Even if you plan to use Visual Studio 2017 as your primary development tool, I recommend that you learn how to use Visual Studio Code and the .NET Core command-line tool as well.

You can download Visual Studio Code from https://code.visualstudio.com/.

Installing Microsoft Visual Studio Code for macOS

In this book, I will show examples and screenshots of Visual Studio Code by using the version for macOS. The steps for doing the same with Visual Studio Code for Windows and variants of Linux is very similar, so I will not repeat the instructions for every platform.

After downloading Visual Studio Code for macOS, drag and drop it to your Applications folder, as shown in the following screenshot:

Installing .NET Core for macOS

You will now need to install the .NET Core SDK for macOS. The full instructions, including a video to watch, are described at the following link, and I have included the basic steps in this book for your convenience: https://www.microsoft.com/net/core#macos.

Installing Homebrew

The first step is to install Homebrew (if you don't already have it).

Start macOS's Terminal app and enter the following command at the prompt:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Terminal will prompt you to press RETURN to continue, and then prompt for your password, as shown in the following screenshot:

Installing OpenSSL

The second step is to use Homebrew to install OpenSSL, which is required by .NET Core.

At the prompt, enter the following commands:

brew updatebrew install opensslmkdir -p /usr/local/libln -s /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib /usr/local/lib/ln -s /usr/local/opt/openssl/lib/libssl.1.0.0.dylib /usr/local/lib/

Terminal will output messages as shown in the following screenshot:

Installing .NET Core SDK

The third step is to download the .NET Core SDK installer for macOS (x64) from the following link: https://www.microsoft.com/net/download/core.

Note

The .NET Core SDK installer package installs .NET Core version 1.1.1 and the .NET Core Command Line Interface (CLI) tool version 1.0.1. Yes, the version numbers are confusing! A single CLI tool with its own version number is used for multiple versions of .NET Core runtime. .NET Core 1.1.1 is the Current branch and gets new features and bug fixes. .NET Core 1.0.4 is the Long Term Support (LTS) branch and only gets bug fixes. Both were released on March 7, 2017 with Visual Studio 2017.

Run the dotnet-1.1.1-sdk-osx-x64.pkg installer package, as shown in the following screenshot:

Click Continue, accept the license agreement, click Install, and then, as shown in the next screenshot, click Close:

Installing the Visual Studio Code extension for C#

This extension is not necessary but it provides IntelliSense as you type, so it's very handy to install.

Launch Visual Studio Code and click the Extensions icon, or choose View | Extensions, or press Cmd + Shift + X .

C# is the most popular extension so you should see it at the top of the list, as shown in the following screenshot:

Click Install, and then click Reload, to reload the window and activate the extension.

Now that you have installed and set up your development environment, you will learn some background about .NET before diving in to writing code.

Understanding .NET

.NET Framework, .NET Core, .NET Standard, and .NET Native are related and overlapping platforms for developers to build applications and services upon.

Understanding .NET Framework

Microsoft's .NET Framework is a development platform that includes a Common Language Runtime (CLR) that manages the execution of code, and provides a rich library of classes to build applications.

Microsoft designed .NET Framework to have the possibility of being cross-platform, but Microsoft put their implementation effort into making it work best with Windows.

Practically speaking, .NET Framework is Windows-only, and a legacy platform.

Understanding the Mono and Xamarin projects

Third parties developed a .NET implementation named the Mono project that you can read more about here: http://www.mono-project.com/.

Mono is cross-platform, but it fell well behind the official implementation of .NET Framework. It has found a niche as the foundation of the Xamarin mobile platform.

Microsoft purchased Xamarin in 2016 and now gives away what used to be an expensive Xamarin extension for free with Visual Studio 2017. Microsoft renamed the Xamarin Studio development tool to Visual Studio for Mac and has given it the ability to create ASP.NET Core Web API services. Xamarin is targeted at mobile development and building cloud services to support mobile apps.

Note

You will use Visual Studio for Mac in Chapter 15, Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API to create a mobile app for iOS and Android that calls an ASP.NET Core Web API service.

Understanding .NET Core

Today, we live in a truly cross-platform world. Modern mobile and cloud development has made Windows a much less important operating system. So, Microsoft has been working on an effort to decouple .NET from its close ties with Windows.

While rewriting .NET to be truly cross-platform, Microsoft has taken the opportunity to refactor .NET to remove major parts that are no longer considered core.

This new product is branded as .NET Core, which includes a cross-platform implementation of the CLR known as CoreCLR, and a streamlined library of classes known as CoreFX.

Scott Hunter, Microsoft Partner Director Program Manager for .NET, says, "Forty percent of our .NET Core customers are brand-new developers to the platform, which is what we want with .NET Core. We want to bring new people in."

The following table shows when important versions of .NET Core were released, and Microsoft's schedule for the next major release:

Version

Released

.NET Core RC1

November 2015

.NET Core 1.0

June 2016

.NET Core 1.1

November 2016

.NET Core 1.0.4 (LTS) and .NET Core (Current) 1.1.1

March 2017

.NET Core 2.0

Scheduled for release in Q3 2017

Tip

Good Practice

If you need to work with .NET Core 1.0 and 1.1, then I recommend that you read the announcement for .NET Core 1.1, although the information at the following URL is useful for all .NET Core developers: https://blogs.msdn.microsoft.com/dotnet/2016/11/16/announcing-net-core-1-1/

Streamlining .NET

.NET Core is much smaller than the current version of .NET Framework because a lot has been removed.

For example, Windows Forms and Windows Presentation Foundation (WPF) can be used to build graphical user interface (GUI) applications, but they are tightly bound to Windows, so they have been removed from .NET Core. The latest technology used to build Windows apps is the Universal Windows Platform (UWP), and UWP is built on a custom version of .NET Core. You will learn about it in Chapter 13, Building Universal Windows Platform Apps Using XAML.

ASP.NET Web Forms and Windows Communication Foundation (WCF) are old web application and service technologies that fewer developers choose to use for new development projects today, so they have also been removed from .NET Core. Instead, developers prefer to use ASP.NET MVC and ASP.NET Web API. These two technologies have been refactored and combined into a new product that runs on .NET Core named ASP.NET Core. You will learn about ASP.NET Core MVC in Chapter 14, Building Web Applications Using ASP.NET Core MVC, and ASP.NET Core Web API in Chapter 15, Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API.

The Entity Framework (EF) 6.x is an object-relational mapping technology to work with data stored in relational databases such as Oracle and Microsoft SQL Server. It has gained baggage over the years, so the cross-platform version has been slimmed down and named Entity Framework Core. You will learn about it in Chapter 8, Working with Databases Using Entity Framework Core.

Some common but old data types in .NET Framework have been removed from .NET Core, such as  HashTable and ArrayList in System.Collections, but can be added back using a separate class library or NuGet package. Some data types in .NET that are included with both .NET Framework and .NET Core have been simplified by removing some members. For example, in .NET Framework, the File class has both a Close and Dispose method, and either can be used to release the file resources. In .NET Core, there is only the Dispose method. This reduces the memory footprint of the assembly and simplifies the API you must learn.

As well as removing large pieces from .NET Framework to make .NET Core, Microsoft has componentized .NET Core into NuGet packages: small chunks of functionality that can be deployed independently.

Note

.NET Framework 4.6 is about 200 MB and must be deployed as a single unit. .NET Core 1.0 is about 11 MB. Eventually, .NET Core and all its NuGet packages may grow to hundreds of megabytes. Microsoft's primary goal is not to make .NET Core smaller than .NET Framework. The goal is to componentize .NET Core to support modern technologies and to have fewer dependencies so that deployment requires only those packages that your application needs.

Understanding .NET Standard

The situation with .NET today is that there are three forked .NET platforms, all controlled by Microsoft:

.NET FrameworkXamarin.NET Core

Each have different strengths and weaknesses because they are designed for different scenarios. This has led to the problem that a developer must learn three platforms, each with annoying quirks and limitations.

So, Microsoft is working on defining .NET Standard 2.0: a set of APIs that all .NET platforms must implement. At the time that I write this, in March 2017, there is .NET Standard 1.6, but only .NET Core supports it; .NET Framework and Xamarin do not.

.NET Standard 2.0 will be implemented by .NET Framework, .NET Core, and Xamarin. For .NET Core, this will add many of the missing APIs that developers need to port old code written for .NET Framework to the cross-platform .NET Core. However, Microsoft warns that some APIs will be "implemented", but throw an exception to indicate to a developer that they should not actually be used! You will learn how to handle this in Chapter 2, Speaking C#.

.NET Standard 2.0 is the near future of .NET, and it will make it much easier for developers to share code between any flavor of .NET, but we are not there yet. Microsoft says .NET Standard 2.0, and .NET Core 2.0, are scheduled for release in Q3 2017. That could mean July 1, 2017, but based on previous experience, I think late September 2017 is more realistic.

The following diagram summarizes how the three variants of .NET (sometimes known as app models) will share the common .NET Standard 2.0 and infrastructure:

.NET used in this book

The first edition of this book focused on .NET Core, but used .NET Framework when important or useful features had not been implemented in .NET Core. Visual Studio 2015 was used for most examples, with Visual Studio Code shown only briefly.

The second edition has been purged of all .NET Framework code examples. It has been rewritten so that all code is pure .NET Core and can be written with either Visual Studio 2017 or Visual Studio Code on any supported operating system.

The only exceptions are in Chapter 13, Building Universal Windows Platform Apps Using XAML, that uses .NET Core for UWP and requires Visual Studio 2017 running on Windows 10, and in Chapter 15, Building Mobile Apps Using Xamarin.Forms and ASP.NET Core Web API, when we will write a Xamarin mobile app with Visual Studio for Mac.

Understanding .NET Native

Another .NET initiative is .NET Native. This compiles C# code to native CPU instructions ahead-of-time (AoT) rather than using the CLR to compile intermediate language (IL) code just-in-time (JIT) to native code later.

.NET Native improves execution speed and reduces the memory footprint for applications. It supports the following:

UWP apps for Windows 10, Windows 10 Mobile, Xbox One, HoloLens, and Internet of Things (IoT) devices such as Raspberry PiServer-side web development with ASP.NET CoreConsole applications for use on the command line

Comparing .NET technologies

The following table summarizes and compares .NET technologies:

Writing and compiling code using the .NET Core CLI tool

When you install Visual Studio 2017, or the .NET Core SDK, a Command Line Interface (CLI) tool named dotnet is installed as well as the .NET Core runtime.

dotnet has the following commands that all work on the project in the current folder:

dotnet new console: creates a new console application projectdotnet new classlib: creates a new assembly library projectdotnet new web: creates a new empty ASP.NET Core projectdotnet new mvc: creates a new ASP.NET Core MVC projectdotnet new webapi: creates a new ASP.NET Core Web API projectdotnet restore: downloads dependencies for the projectdotnet build: compiles the projectdotnet test: runs unit tests on the projectdotnet run: runs the projectdotnet migrate: migrates a .NET Core project created with the preview CLI tools to the current CLI tool MS Build formatdotnet pack: creates a NuGet package for the projectdotnet publish: compiles and publishes the project, either with dependencies or as a self-contained application

Note

You will learn how to build, package, publish, and deploy your .NET Core applications and assemblies in Chapter 16, Packaging and Deploying Your Code Cross-Platform.

Before we use CLI tools such as dotnet, we need to write some code!

Writing code using a simple text editor

If you are using Windows, start Notepad.

If you are using macOS, launch TextEdit. From the TextEdit menu, choose Preferences, clear the Smart quotes check box, and then close the dialog. From the Format menu, choose Make Plain Text.

Or run your favorite plain text editor.

Enter the following code:

class MyApp { static void Main() { System.Console.WriteLine("Hello, C#!"); } }

Note

C# is case sensitive, meaning that you must type uppercase and lowercase characters exactly as shown in the preceding code. C# is not whitespace sensitive, meaning that it does not care if you use tabs, spaces, and carriage-returns to layout your code however you like.

You can type the code all in one line or spread it out over multiple lines and indent your lines. For example, the following code would also compile and have the same output:

class MyApp { static void Main (){System. Console. WriteLine( "Hello, C#!"); } }

Of course, it's best to write your code in a way that other programmers, and yourself months or years later, can clearly read!

If you are using Windows Notepad

In Notepad, from the File menu, choose Save As....

In the dialog box, change to drive C: (or any drive which you want to use to save your projects), click on the New folder button, and name the folder Code. Open the Code folder, and click the New folder button, and name the folder Chapter01. Open the Chapter01 folder, and click the New folder button, and name the folder Ch01_HelloCS. Open the Ch01_HelloCS folder.

In the Save as type field, select All Files from the drop-down list to avoid appending the .txt file extension, and enter the file name as MyApp.cs, as shown in the following screenshot:

Your code in Notepad should look something like the following screenshot:

If you are using macOS TextEdit

In TextEdit, from the File menu, choose Save..., or press Cmd + S.

In the dialog box, change to your user folder (mine is named markjprice) or any directory in which you want to use to save your projects, click on the New Folder button, and name the folder Code. Open the Code folder, and click the New Folder button, and name the folder Chapter01. Open the Chapter01 folder, and click the New Folder button, and name the folder Ch01_HelloCS. Open the Ch01_HelloCS folder.

In the Plain Text Encoding field, select Unicode (UTF-8) from the drop-down list, uncheck the box for If no extension is provided, use ".txt" to avoid appending the .txt file extension, enter the filename as MyApp.cs, and click on Save, as shown in the following screenshot:

Compiling code using the .NET Core CLI tool

If you are using Windows, start Command Prompt.

If you are using macOS, launch Terminal.

At the prompt, enter the following command:

dotnet

You should see the following output describing the dotnet CLI tool:

Note

The output from the dotnet command-line tool will be identical on Windows, macOS, and Linux.

Enter the following commands at the prompt to:

Change to the folder for the projectCreate a new console application in the directoryList the files that the dotnet command-line tool created

If you are using Windows, in Command Prompt, enter:

cd C:\Code\Chapter01\Ch01_HelloCSdotnet new consoledir

If you are using macOS, in Terminal, enter:

cd Code/Chapter01/Ch01_HelloCSdotnet new consolels

Note

The first time that you execute a dotnet new command, your local package cache must be populated. This should only take a few moments.

You should see that the dotnet tool has created two new files for you:

Program.cs: source code for a simple console applicationCh01_HelloCS.csproj: a project file that lists dependencies and project-related configuration

For this example, we must delete the file named Program.cs since we have already created our own class called Program in the file named MyApp.cs.

If you are using Windows, in Command Prompt:

del Program.cs

If you are using macOS, in Terminal:

rm Program.cs

Note

In all future examples, we will use the Program.cs