Slides and Code from “Using C#’s Async Effectively”

The slides and code from my talk on the new async language features in C# and VB.Net are now available on

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Launching a WPF Window in a Separate Thread, Part 1

Typically, I strongly recommend keeping the user interface within an application’s main thread, and using multiple threads to move the actual “work” into background threads.  However, there are rare times when creating a separate, dedicated thread for a Window can be beneficial.  This is even acknowledged in the MSDN samples, such as the Multiple Windows, Multiple Threads* sample.  However, doing this correctly is difficult.  Even the referenced MSDN sample has major flaws, and will fail horribly in certain scenarios.  To ease this, I wrote a small class that alleviates some of the difficulties involved.

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C# Performance Pitfall – Interop Scenarios Change the Rules

C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#.

I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be…

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Async CTP Refresh for Visual Studio 2010 SP1 Released

The Visual Studio team today released an update to the Visual Studio Async CTP which allows it to be used with Visual Studio SP1.  This new CTP includes some very nice new additions over the previous CTP.  The main highlights of this release include:

  • Compatibility with Visual Studio SP1
  • APIs for Windows Phone 7
  • Compatibility with non-English installations
  • Compatibility with Visual Studio Express Edition
  • More efficient Async methods due to a change in the API
  • Numerous bug fixes
  • New EULA which allows distribution in production environments
  • Anybody using the Async CTP should consider upgrading to the new version immediately.  For details, visit the Visual Studio Asynchronous Programming page on MSDN.

ConcurrentDictionary<TKey,TValue> used with Lazy<T>

In a recent thread on the MSDN forum for the TPL, Stephen Toub suggested mixing ConcurrentDictionary<T,U> with Lazy<T>.  This provides a fantastic model for creating a thread safe dictionary of values where the construction of the value type is expensive.  This is an incredibly useful pattern for many operations, such as value caches.

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C# 5 Async, Part 3: Preparing Existing code For Await

While the Visual Studio Async CTP provides a fantastic model for asynchronous programming, it requires code to be implemented in terms of Task and Task<T>.  The CTP adds support for Task-based asynchrony to the .NET Framework methods, and promises to have these implemented directly in the framework in the future.  However, existing code outside the framework will need to be converted to using the Task class prior to being usable via the CTP.

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C# 5 Async, Part 2: Asynchrony Today

The .NET Framework has always supported asynchronous operations.  However, different mechanisms for supporting exist throughout the framework.  While there are at least three separate asynchronous patterns used through the framework, only the latest is directly usable with the new Visual Studio Async CTP.  Before delving into details on the new features, I will talk about existing asynchronous code, and demonstrate how to adapt it for use with the new pattern.

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C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

Today’s announcement at PDC of the future directions C# is taking excite me greatly.  The new Visual Studio Async CTP is amazing.  Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability.  This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await.

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Parallelism in .NET – Part 20, Using Task with Existing APIs

Although the Task class provides a huge amount of flexibility for handling asynchronous actions, the .NET Framework still contains a large number of APIs that are based on the previous asynchronous programming model.  While Task and Task<T> provide a much nicer syntax as well as extending the flexibility, allowing features such as continuations based on multiple tasks, the existing APIs don’t directly support this workflow.

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Parallelism in .NET – Part 19, TaskContinuationOptions

My introduction to Task continuations demonstrates continuations on the Task class.  In addition, I’ve shown how continuations allow handling of multiple tasks in a clean, concise manner.  Continuations can also be used to handle exceptional situations using a clean, simple syntax.

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