Book Image

C# 6 and .NET Core 1.0

Book Image

C# 6 and .NET Core 1.0

Overview of this book

With the release of .NET Core 1.0, you can now create applications for Mac OS X and Linux, as well as Windows, using the development tools you know and love. C# 6 and .NET Core 1.0 has been divided into three high-impact sections to help start putting these new features to work. First, we'll run you through the basics of C#, as well as object-orient programming, before taking a quick tour through the latest features of C# 6 such as string interpolation for easier variable value output, exception filtering, and how to perform static class imports. We'll also cover both the full-feature, mature .NET Framework and the new, cross-platform .NET Core. After quickly taking you through C# and how .NET works, we'll dive into the internals of the .NET class libraries, covering topics such as performance, monitoring, debugging, internationalization, serialization, and encryption. We'll look at Entity Framework Core 1.0 and how to develop Code-First entity data models, as well as how to use LINQ to query and manipulate that data. The final section will demonstrate the major types of applications that you can build and deploy cross-device and cross-platform. In this section, we'll cover Universal Windows Platform (UWP) apps, web applications, and web services. Lastly, we'll help you build a complete application that can be hosted on all of today's most popular platforms, including Linux and Docker. By the end of the book, you'll be armed with all the knowledge you need to build modern, cross-platform applications using C# and .NET Core.
Table of Contents (25 chapters)
C# 6 and .NET Core 1.0
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Chapter 9 – Querying and Manipulating Data with LINQ


  1. What are the two requirements to use LINQ?

    You must import the System.Linq namespace to make the LINQ extension methods available and reference a LINQ provider assembly for the type of data that you want to work with.

  2. Which LINQ extension method would you use to return a subset of properties from a type?

    The Select method allows projection (selection) of properties.

  3. Which LINQ extension method would you use to filter results?

    The Where method allows filtering by supplying a delegate (or lambda expression) that returns a Boolean to indicate whether the value should be included in the results.

  4. List five LINQ extension methods that perform aggregation.

    Max, Min, Count, Average, Sum, and Aggregate.

  5. What is the difference between the Select and SelectMany extension methods?

    Select returns exactly what you specify to return. SelectMany checks that the items you have selected are themselves IEnumerable<T> and then breaks them down into smaller parts. For example, if the type you select is a string value (which is IEnumerable<char>), SelectMany will break each string value returned into their individual char values.