All about asynchronous programming from .NET starting from initial framework to latest version. We will be looking into almost all features from .NET which are related to Asynchronous Programming. This seminar will cover up evolution of asynchronous programming and slowly moving to Task.

1. Asynchronous Programming in C#
- Part 1
Presenter: Vikash Kumar, Mindfire Solutions
(28/07/2014)

2. About Me
MCTS-70-515 - Microsoft .NET 4.0, Web App
Development
MCP:70-483: MS - Programming in C#
Skills: MVC, Asp.Net WebForms, C#,
EntityFramework, OpenAccess, TypeScript,
SEO, jQuery, KendoUI, Lucene.Net,
Asynchronous programming, Sql Server.
Connect Me:
Blog :- http://vikutech.blogspot.in/
Twitter :- https://twitter.com/viku85
LinkedIn :- http://www.linkedin.com/pub/vikash-kumar/11/4b5/625
Google+ :- https://plus.google.com/108754146104237310375
Contact Me:
Email :- vikashk@mindfiresolutions.com / viku85@gmail.com
Skype :- mfsi_vikash

3. Agenda

What is asynchronous?

Asynchronous programming options and history

Thread and ThreadPool

Asynchronous Programming Model (APM)

Event-based Asynchronous Pattern (EAP)

Task
– Basics
– Exception handling
– Relationships

4. What is asynchronous?
Image Source: http://www.webopedia.com/
To do more than one thing at a time.
asyn = not with
chronos = time

5. Asynchronous programming
options and history

Thread

Asynchronous Programming Model (APM)

Event-Based Asynchronous Pattern (EAP)

BackgroundWorker

Task

Task Parallel Library - DataFlow

Task Parallel Library – Parallel APIs

Thread → APM → EAP → TAP

6. Thread and ThreadPool

Basic building block for async programming.

Parameterize thread, came with .NET 2.0
Image source:http://johnpaulmorabito.blogspot.in/

7. APM and EAP

APM depends upon Begin and End methods.

Callbacks are dependent on IAsyncResult.

EAP came with .NET 2.0 which automatically
handles synchronization context.

BackgroundWorker is an example of EAP based
programming.

EAP can be seen while adding web reference
which automatically creates with proxies classes.

8. APM and EAP

9. Task

A task is an abstraction of unit of work to run
asynchronously.

Ways to execute: new Task(Speak).Start(),
Task.Factory.StartNew(Speak),
Task.Run(Speak)

Use FromAsync when an API has
BeginXXX/EndXXX.

Task can be canceled through
CancellationToken and checked with
ThrowIfCancellationRequested.

IProgress<T> came with 4.5 which can be
used to show status

10. Task error handling

Task are completed with following state: Ran to
Completion, Canceled and Faulted.

Task uses AggregateException to wrap up any
other exception occurs which can be found under
inner exception.

AggregateException comes with Flatten method to
check all exceptions.

AggregateException also comes with Handle
method which accepts predicate to handle errors.

ThrowUnobservedTaskExceptions to configure
to shallow exception.

11. Cancellation
FromAsync

12. Progress bar
Exception handling

13. Task Relationships
Task
Task Task Task
Child Tasks
Task Task Task
Chained Task

14. Task Relationships...

ContinueWhenXXX can be used to chain up
tasks with TaskContinuationOptions enum for
various conditions.

TaskCreationOptions.AttachedToParent is
used to create child tasks.

Creating child task will reflect exception in parent
task if exception occurs.

Task.Run uses
TaskCreationOptions.DenyChildAttach by
default which will act as nested task.

15. Task Relationship

16. Presenter: XXXX XXXX, Mindfire Solutions
Question and
Answer

17. References

Pro Asynchronous Programming with .NET
 Asynchronous Programming Patterns
 Asynchronous Programming in .NET: I'll Call You Bac
(For definition)

18. Presenter: Vikash Kumar, Mindfire Solutions
Thank you

19. www.mindfiresolutions.com
https://www.facebook.com/MindfireSolutions
http://www.linkedin.com/company/mindfire-solutions
http://twitter.com/mindfires