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)

Inheriting and extending .NET types

.NET has prebuilt class libraries containing hundreds of thousands of types. Rather than creating your own completely new types, you can often get a head start by deriving from one of Microsoft's types to inherit some or all of its behavior and then overriding or extending it.

Inheriting exceptions

As an example of inheritance, we will derive a new type of exception:

  1. In the PacktLibrary project, add a new class named PersonException, with three constructors, as shown in the following code:
    using System;
    namespace Packt.Shared 
      public class PersonException : Exception 
        public PersonException() : base() { } 
        public PersonException(string message) : base(message) { }
        public PersonException(
          string message, Exception innerException)
          : base(message, innerException) { } 

    Unlike ordinary methods, constructors are not inherited, so we must explicitly declare and explicitly...