Book Image

Learn C# Programming

By : Marius Bancila, Raffaele Rialdi, Ankit Sharma
5 (1)
Book Image

Learn C# Programming

5 (1)
By: Marius Bancila, Raffaele Rialdi, Ankit Sharma

Overview of this book

The C# programming language is often developers’ primary choice for creating a wide range of applications for desktop, cloud, and mobile. In nearly two decades of its existence, C# has evolved from a general-purpose, object-oriented language to a multi-paradigm language with impressive features. This book will take you through C# from the ground up in a step-by-step manner. You'll start with the building blocks of C#, which include basic data types, variables, strings, arrays, operators, control statements, and loops. Once comfortable with the basics, you'll then progress to learning object-oriented programming concepts such as classes and structures, objects, interfaces, and abstraction. Generics, functional programming, dynamic, and asynchronous programming are covered in detail. This book also takes you through regular expressions, reflection, memory management, pattern matching, exceptions, and many other advanced topics. As you advance, you'll explore the .NET Core 3 framework and learn how to use the dotnet command-line interface (CLI), consume NuGet packages, develop for Linux, and migrate apps built with .NET Framework. Finally, you'll understand how to run unit tests with the Microsoft unit testing frameworks available in Visual Studio. By the end of this book, you’ll be well-versed with the essentials of the C# language and be ready to start creating apps with it.
Table of Contents (20 chapters)

Delegates and events

A callback is a function (or more generally, any executable code) that is passed as a parameter to another function in order to be called immediately (synchronous callbacks) or at a later time (asynchronous callbacks). Operating systems (such as Windows) use callbacks extensively to allow applications to respond to events such as mouse events or key presses. Another typical example for callbacks is general purpose algorithms that use callbacks for processing elements from a collection, such as comparing them in order to sort them or filter them out.

In languages such as C and C++, a callback is simply a function pointer (that is, the address of a function). However, in .NET, callbacks are strongly-typed objects that hold not only the reference to one or more methods but also the information about their parameters and return type. In .NET and C#, callbacks are represented by delegates.

Delegates

A delegate is defined using the delegate keyword. The declaration...