Book Image

C# 9 and .NET 5 – Modern Cross-Platform Development - Fifth Edition

By : Mark J. Price
Book Image

C# 9 and .NET 5 – Modern Cross-Platform Development - Fifth Edition

By: Mark J. Price

Overview of this book

In C# 9 and .NET 5 – Modern Cross-Platform Development, Fifth Edition, expert teacher Mark J. Price gives you everything you need to start programming C# applications. This latest edition uses the popular Visual Studio Code editor to work across all major operating systems. It is fully updated and expanded with a new chapter on the Microsoft Blazor framework. The book’s first part teaches the fundamentals of C#, including object-oriented programming and new C# 9 features such as top-level programs, target-typed new object instantiation, and immutable types using the record keyword. Part 2 covers the .NET APIs, for performing tasks like managing and querying data, monitoring and improving performance, and working with the file system, async streams, serialization, and encryption. Part 3 provides examples of cross-platform apps you can build and deploy, such as websites and services using ASP.NET Core or mobile apps using Xamarin.Forms. The best type of application for learning the C# language constructs and many of the .NET libraries is one that does not distract with unnecessary application code. For that reason, the C# and .NET topics covered in Chapters 1 to 13 feature console applications. In Chapters 14 to 20, having mastered the basics of the language and libraries, you will build practical applications using ASP.NET Core, Model-View-Controller (MVC), and Blazor. By the end of the book, you will have acquired the understanding and skills you need to use C# 9 and .NET 5 to create websites, services, and mobile apps.
Table of Contents (23 chapters)

Raising and handling events

Methods are often described as actions that an object can perform, either on itself or to related objects. For example, List can add an item to itself or clear itself, and File can create or delete a file in the filesystem.

Events are often described as actions that happen to an object. For example, in a user interface, Button has a Click event, a click being something that happens to a button. Another way of thinking of events is that they provide a way of exchanging messages between two objects.

Events are built on delegates, so let's start by having a look at how delegates work.

Calling methods using delegates

You have already seen the most common way to call or execute a method: use the . operator to access the method using its name. For example, Console.WriteLine tells the Console type to access its WriteLine method.

The other way to call or execute a method is to use a delegate. If you have used languages that support function...