C# 12 and .NET 8 – Modern Cross-Platform Development Fundamentals, Eighth Edition: Start building websites and services with ASP.NET Core 8, Blazor, and EF Core 8

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1. Chapter 1: Hello, C#! Welcome, .NET!
2. Chapter 2: Speaking C#
3. Chapter 3: Controlling Flow, Converting Types, and Handling Exceptions
4. Chapter 4: Writing, Debugging, and Testing...

Introducing this book and its contents

Let’s get started by introducing you to the code solutions and structure of this book.

Getting code solutions for this book

The GitHub repository for this book has solutions using full application projects for all code tasks and exercises, found at the following link:

https://github.com/markjprice/cs12dotnet8

After navigating to the GitHub repository in your web browser, press the . (dot) key on your keyboard, or manually change .com to .dev in the link to convert the repository into a live code editor based on Visual Studio Code using GitHub Codespaces, as shown in Figure 1.1:

Figure 1.1: GitHub Codespaces live editing the book’s GitHub repository

We provide you with a PDF file that has color images of the screenshots and diagrams used in this book. You can download this file from https://packt.link/gbp/9781837635870.

Visual Studio Code in a web browser is great to run alongside your...

Setting up your development environment

Before you start programming, you’ll need a code editor for C#. Microsoft has a family of code editors and Integrated Development Environments (IDEs), which include:

• Visual Studio 2022 for Windows
• Visual Studio Code for Windows, Mac, or Linux
• Visual Studio Code for the Web or GitHub Codespaces

Third parties have created their own C# code editors, for example, JetBrains Rider, which is available for Windows, Mac, or Linux but does have a license cost. JetBrains Rider is popular with more experienced .NET developers.

Warning! Although JetBrains is a fantastic company with great products, both Rider and the ReSharper extension for Visual Studio are software, and all software has bugs and quirky behavior. For example, they might show errors like “Cannot resolve symbol” in your Razor Pages, Razor views, and Blazor components. Yet you can build and run those files because there is no...

Understanding .NET

“Those who cannot remember the past are condemned to repeat it.”

– George Santayana

.NET, .NET Core, .NET Framework, and Xamarin are related and overlapping platforms for developers used to build applications and services.

If you are not familiar with the history of .NET, then I introduce you to each of these .NET concepts at the following link:

https://github.com/markjprice/cs12dotnet8/blob/main/docs/ch01-dotnet-history.md

Understanding .NET support

.NET versions are either Long Term Support (LTS), Standard Term Support (STS) (formerly known as Current), or Preview, as described in the following list:

• LTS releases are a good choice for applications that you do not intend to update frequently, although you must update the .NET runtime for your production code monthly. LTS releases are supported by Microsoft for 3 years after General Availability (GA), or 1 year after the next LTS release ships...

Building console apps using Visual Studio 2022

The goal of this section is to showcase how to build a console app using Visual Studio 2022 for Windows.

If you do not have a Windows computer or want to use Visual Studio Code, then you can skip this section since the code will be the same; just the tooling experience is different. But I recommend that you review this section because it does explain some of the code and how top-level programs work, and that information applies to all code editors.

This section is also available in the GitHub repository (so it can be updated after publishing if needed) at the following link:

https://github.com/markjprice/cs12dotnet8/blob/main/docs/code-editors/vs4win.md

If you want to see similar instructions for using JetBrains Rider, they are available in the GitHub repository at the following link:

https://github.com/markjprice/cs12dotnet8/blob/main/docs/code-editors/rider.md

Writing code using Visual Studio 2022

Let’...

Building console apps using Visual Studio Code

The goal of this section is to showcase how to build a console app using Visual Studio Code and the dotnet CLI.

If you never want to try Visual Studio Code or the dotnet command-line tool, then please feel free to skip this section, and then continue with the Making good use of the GitHub repository for this book section.

Both the instructions and screenshots in this section are for Windows, but the same actions will work with Visual Studio Code on the macOS and Linux variants.

The main differences will be native command-line actions such as deleting a file: both the command and the path are likely to be different on Windows or macOS and Linux. Luckily, the dotnet CLI tool itself and its commands are identical on all platforms.

Writing code using Visual Studio Code

Let’s get started writing code!

1. Start your favorite tool for working with the filesystem, for example, File Explorer on Windows or Finder...

Making good use of the GitHub repository for this book

Git is a commonly used source code management system. GitHub is a company, website, and desktop application that makes it easier to manage Git. Microsoft purchased GitHub in 2018, so it will continue to get closer integration with Microsoft tools.

I created a GitHub repository for this book, and I use it for the following:

• To store the solution code for the book that can be maintained after the print publication date.
• To provide extra materials that extend the book, like errata fixes, small improvements, lists of useful links, and optional sections about topics that cannot fit in the printed book.
• To provide a place for readers to get in touch with me if they have issues with the book.

Good Practice: I strongly recommend that all readers review the errata, improvements, post-publication changes, and common errors pages before attempting any coding task in this book. You can find them...

Looking for help

This section is all about how to find quality information about programming on the web.

Reading the documentation on Microsoft Learn

The definitive resource for getting help with Microsoft developer tools and platforms is in the technical documentation on Microsoft Learn, and you can find it at the following link: https://learn.microsoft.com/en-us/docs.

Documentation links in this book

The official Microsoft documentation for .NET needs to cover all versions. The default version shown in the documentation is always the most recent GA version.

For example, between November 2023 and November 2024, the default version of .NET shown in documentation pages will be 8.0. Between November 2024 and November 2025, the default version of .NET will be 9.0. The following link will automatically direct to the current version depending on the current date:

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.stringsyntaxattribute

...

Practicing and exploring

Let’s now test your knowledge and understanding by trying to answer some questions, getting some hands-on practice, and going into the topics covered throughout this chapter in greater detail.

Exercise 1.1 – Test your knowledge

Try to answer the following questions, remembering that although most answers can be found in this chapter, you should do some online research or code writing to answer others:

1. Is Visual Studio 2022 better than Visual Studio Code?
2. Are .NET 5 and later better than .NET Framework?
3. What is .NET Standard and why is it still important?
4. Why can a programmer use different languages, for example, C# and F#, to write applications that run on .NET?
5. What is a top-level program and how do you access any command-line arguments?
6. What is the name of the entry point method of a .NET console app and how should it be explicitly declared if you are not using the top-level program feature?
...

Summary

In this chapter, we:

• Set up your development environment.
• Discussed the similarities and differences between modern .NET, .NET Core, .NET Framework, Xamarin, and .NET Standard in an online article.
• Used Visual Studio 2022 and Visual Studio Code with the .NET SDK CLI to create a couple of simple console apps grouped in a solution.
• Learned how to download the solution code for this book from its GitHub repository.
• Learned how to find help. This could be in the traditional way, by using help command switches, documentation, and articles, or the modern way, by having a conversation with a coding expert AI, or using an AI-based tool to perform “grunt work.”

In the next chapter, you will learn how to “speak” C#.

Learn more on Discord

To join the Discord community for this book – where you can share feedback, ask questions to the author, and learn about new releases – follow the QR code below:

https://packt.link/csharp12dotnet8