Book Image

Multithreading with C# Cookbook, Second Edition - Second Edition

By : Evgenii Agafonov
Book Image

Multithreading with C# Cookbook, Second Edition - Second Edition

By: Evgenii Agafonov

Overview of this book

Multi-core processors are synonymous with computing speed and power in today’s world, which is why multithreading has become a key concern for C# developers. Multithreaded code helps you create effective, scalable, and responsive applications. This is an easy-to-follow guide that will show you difficult programming problems in context. You will learn how to solve them with practical, hands-on, recipes. With these recipes, you’ll be able to start creating your own scalable and reliable multithreaded applications. Starting from learning what a thread is, we guide you through the basics and then move on to more advanced concepts such as task parallel libraries, C# asynchronous functions, and much more. Rewritten to the latest C# specification, C# 6, and updated with new and modern recipes to help you make the most of the hardware you have available, this book will help you push the boundaries of what you thought possible in C#.
Table of Contents (18 chapters)
Multithreading with C# Cookbook Second Edition
About the Author
About the Reviewers

Foreground and background threads

This recipe will describe what foreground and background threads are and how setting this option affects the program's behavior.

Getting ready

To work through this recipe, you will need Visual Studio 2015. There are no other prerequisites. The source code for this recipe can be found at BookSamples\Chapter1\Recipe7.

How to do it...

To understand the effect of foreground and background threads on a program, perform the following steps:

  1. Start Visual Studio 2015. Create a new C# console application project.

  2. In the Program.cs file, add the following using directives:

    using System;
    using System.Threading;
    using static System.Console;
    using static System.Threading.Thread;
  3. Add the following code snippet below the Main method:

    class ThreadSample
      private readonly int _iterations;
      public ThreadSample(int iterations)
        _iterations = iterations;
      public void CountNumbers()
        for (int i = 0; i < _iterations; i++)
          WriteLine($"{CurrentThread.Name} prints {i}");
  4. Add the following code snippet inside the Main method:

    var sampleForeground = new ThreadSample(10);
    var sampleBackground = new ThreadSample(20);
    var threadOne = new Thread(sampleForeground.CountNumbers);
    threadOne.Name = "ForegroundThread";
    var threadTwo = new Thread(sampleBackground.CountNumbers);
    threadTwo.Name = "BackgroundThread";
    threadTwo.IsBackground = true;
  5. Run the program.

How it works...

When the main program starts, it defines two different threads. By default, a thread that we create explicitly is a foreground thread. To create a background thread, we manually set the IsBackground property of the threadTwo object to true. We configure these threads in a way that the first one will be completed faster, and then we run the program.

After the first thread is complete, the program shuts down and the background thread is terminated. This is the main difference between the two: a process waits for all the foreground threads to complete before finishing the work, but if it has background threads, they just shut down.

It is also important to mention that if a program defines a foreground thread that does not get completed; the main program does not end properly.