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
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Aborting a thread


In this recipe, we will describe how to abort another thread's execution.

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\Recipe4.

How to do it...

To understand how to abort another thread's execution, 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;
  3. Using the static System.Threading.Thread, add the following code snippet below the Main method:

    static void PrintNumbersWithDelay()
    {
      WriteLine("Starting...");
      for (int i = 1; i < 10; i++)
      {
        Sleep(TimeSpan.FromSeconds(2));
        WriteLine(i);
      }
    }
  4. Add the following code snippet inside the Main method:

    WriteLine("Starting program...");
    Thread t = new Thread(PrintNumbersWithDelay);
    t.Start();
    Thread.Sleep(TimeSpan.FromSeconds(6));
    t.Abort();
    WriteLine("A thread has been aborted");
    Thread t = new Thread(PrintNumbers);
    t.Start();
    PrintNumbers();
  5. Run the program.

How it works...

When the main program and a separate number-printing thread run, we wait for six seconds and then call a t.Abort method on a thread. This injects a ThreadAbortException method into a thread, causing it to terminate. It is very dangerous, generally because this exception can happen at any point and may totally destroy the application. In addition, it is not always possible to terminate a thread with this technique. The target thread may refuse to abort by handling this exception by calling the Thread.ResetAbort method. Thus, it is not recommended that you use the Abort method to close a thread. There are different methods that are preferred, such as providing a CancellationToken object to cancel a thread execution. This approach will be described in Chapter 3, Using a Thread Pool.