Async in C# 5.0

Async in C# 5.0

by Alex Davies
Released September 2012
Publisher(s): O'Reilly Media, Inc.
ISBN: 9781449337162

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Book description

If you’re writing one of several applications that call for asynchronous programming, this concise hands-on guide shows you how the async feature in C# 5.0 can make the process much simpler. Along with a clear introduction to asynchronous programming, you get an in-depth look at how the async feature works and why you might want to use it in your application.

Written for experienced C# programmers—yet approachable for beginners—this book is packed with code examples that you can extend for your own projects.

  • Write your own asynchronous code, and learn how async saves you from this messy chore
  • Discover new performance possibilities in ASP.NET web server code
  • Explore how async and WinRT work together in Windows 8 applications
  • Learn the importance of the await keyword in async methods
  • Understand which .NET thread is running your code—and at what points in the program
  • Use the Task-based Asynchronous Pattern (TAP) to write asynchronous APIs in .NET
  • Take advantage of parallel computing in modern machines
  • Measure async code performance by comparing it with alternatives

Table of contents

  1. Preface
    1. Intended Audience
    2. How to Read This Book
    3. Conventions Used in This Book
    4. Using Code Examples
    5. Safari® Books Online
    6. How to Contact Us
    7. Acknowledgments
  2. 1. Introduction
    1. Asynchronous Programming
    2. What’s So Great About Asynchronous Code?
    3. What Is Async?
    4. What Async Does
    5. Async Doesn’t Solve Everything
  3. 2. Why Programs Need to Be Asynchronous
    1. Desktop User Interface Applications
      1. An Analogy: The Cafe
    2. Web Application Server Code
      1. Another Analogy: The Restaurant Kitchen
    3. Silverlight, Windows Phone, and Windows 8
    4. Parallel Code
    5. An Example
  4. 3. Writing Asynchronous Code Manually
    1. Some Asynchronous Patterns Used in .NET
    2. The Simplest Asynchronous Pattern
    3. An Introduction to Task
    4. The Problem with Manual Asynchrony
    5. Converting the Example to Use Manual Asynchronous Code
  5. 4. Writing Async Methods
    1. Converting the Favicon Example to Async
    2. Task and await
    3. Async Method Return Types
    4. Async, Method Signatures, and Interfaces
    5. The return Statement in Async Methods
    6. Async Methods Are Contagious
    7. Async Anonymous Delegates and Lambdas
  6. 5. What await Actually Does
    1. Hibernating and Resuming a Method
    2. The State of the Method
    3. Context
    4. Where await Can’t Be Used
      1. catch and finally Blocks
      2. lock Blocks
      3. LINQ Query Expressions
      4. Unsafe Code
    5. Exception Capture
    6. Async Methods Are Synchronous Until Needed
  7. 6. The Task-Based Asynchronous Pattern
    1. What the TAP Specifies
    2. Using Task for Compute-Intensive Operations
    3. Creating a Puppet Task
    4. Interacting with Old Asynchronous Patterns
    5. Cold and Hot Tasks
    6. Up-Front Work
  8. 7. Utilities for Async Code
    1. Delaying for a Period of Time
    2. Waiting for a Collection of Tasks
    3. Waiting for Any One Task from a Collection
    4. Creating Your Own Combinators
    5. Cancelling Asynchronous Operations
    6. Returning Progress During an Asynchronous Operation
  9. 8. Which Thread Runs My Code?
    1. Before the First await
    2. During the Asynchronous Operation
    3. SynchronizationContext in Detail
    4. await and SynchronizationContext
    5. The Lifecycle of an Async Operation
    6. Choosing Not to Use SynchronizationContext
    7. Interacting with Synchronous Code
  10. 9. Exceptions in Async Code
    1. Exceptions in Async Task-Returning Methods
    2. Unobserved Exceptions
    3. Exceptions in Async void Methods
    4. Fire and Forget
    5. AggregateException and WhenAll
    6. Throwing Exceptions Synchronously
    7. finally in Async Methods
  11. 10. Parallelism Using Async
    1. await and locks
    2. Actors
    3. Using Actors in C#
    4. Task Parallel Library Dataflow
  12. 11. Unit Testing Async Code
    1. The Problem with Unit Testing in Async
    2. Writing Working Async Tests Manually
    3. Using Unit Test Framework Support
  13. 12. Async in ASP.NET Applications
    1. Advantages of Asynchronous Web Server Code
    2. Using Async in ASP.NET MVC 4
    3. Using Async in Older Versions of ASP.NET MVC
    4. Using Async in ASP.NET Web Forms
  14. 13. Async in WinRT Applications
    1. What Is WinRT?
    2. IAsyncAction and IAsyncOperation<T>
    3. Cancellation
    4. Progress
    5. Providing Asynchronous Methods in a WinRT Component
  15. 14. The Async Compiler Transform—in Depth
    1. The stub Method
    2. The State Machine Struct
    3. The MoveNext Method
      1. Your Code
      2. Transforming Returns to Completions
      3. Get to the Right Place in the Method
      4. Pausing the Method for the await
      5. Resuming after the Await
      6. Completing Synchronously
      7. Catching Exceptions
      8. More Complicated Code
    4. Writing Custom Awaitable Types
    5. Interacting with the Debugger
  16. 15. The Performance of Async Code
    1. Measuring Async Overhead
    2. Async Versus Blocking for a Long-Running Operation
    3. Optimizing Async Code for a Long-Running Operation
    4. Async Versus Manual Asynchronous Code
    5. Async Versus Blocking Without a Long-Running Operation
    6. Optimizing Async Code Without a Long-Running Operation
    7. Async Performance Summary
  17. About the Author
  18. Copyright

Product information

  • Title: Async in C# 5.0
  • Author(s): Alex Davies
  • Release date: September 2012
  • Publisher(s): O'Reilly Media, Inc.
  • ISBN: 9781449337162