Book Image

C# 10 and .NET 6 – Modern Cross-Platform Development - Sixth Edition

By : Mark J. Price
5 (1)
Book Image

C# 10 and .NET 6 – Modern Cross-Platform Development - Sixth Edition

5 (1)
By: Mark J. Price

Overview of this book

Extensively revised to accommodate all the latest features that come with C# 10 and .NET 6, this latest edition of our comprehensive guide will get you coding in C# with confidence. You’ll learn object-oriented programming, writing, testing, and debugging functions, implementing interfaces, and inheriting classes. The book covers the .NET APIs for performing tasks like managing and querying data, monitoring and improving performance, and working with the filesystem, async streams, and serialization. You’ll build and deploy cross-platform apps, such as websites and services using ASP.NET Core. Instead of distracting you with unnecessary application code, the first twelve chapters will teach you about C# language constructs and many of the .NET libraries through simple console applications. In later chapters, having mastered the basics, you’ll then build practical applications and services using ASP.NET Core, the Model-View-Controller (MVC) pattern, and Blazor.
Table of Contents (20 chapters)
19
Index

Working with null values

You have seen how to store primitive values like numbers in struct variables. But what if a variable does not yet have a value? How can we indicate that? C# has the concept of a null value, which can be used to indicate that a variable has not been set.

Making a value type nullable

By default, value types like int and DateTime must always have a value, hence their name. Sometimes, for example, when reading values stored in a database that allows empty, missing, or null values, it is convenient to allow a value type to be null. We call this a nullable value type.

You can enable this by adding a question mark as a suffix to the type when declaring a variable.

Let's see an example:

  1. Use your preferred coding tool to add a new Console Application to the Chapter06 workspace/solution named NullHandling. This section requires a full application with a project file, so you will not be able to use a .NET Interactive notebook.
  2. In...