Lucian Wischik
I'm on the VB/C# language design team at Microsoft
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Analyzer sample in Dev14 CTP3This video walks through two sample Roslyn Analyzers.
One analyzer gives squiggles where you could improve your code with the new C#6 language features - nameof(), ?. and primary constructors.
Another analyzer gives squiggles for a XAML performance tip - allocating repeated heap allocations of PropertyChangedEventArgs...
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Tip 6: Async library methods should consider using Task.ConfigureAwait(false)6. Libraries should consider Task.ConfigureAwait(false). This is another micro-optimization you can use to reduce your methods' impact on the UI thread. Consider this if your library routine might be called from the UI thread, and has chatty awaits inside it.
Slides, codes and transcript for...
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Tip 5: Async libraries APIs should be chunky5. Libraries should have chunky async APIs.
But if you can't achieve that, there's a micro-optimization you can use for async methods based around the fast-path which can reduce or eliminate the heap overhead of async methods. As always, don't micro-optimize prematurely...
Slides, source code...
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Tip 4: Async Library Methods Shouldn't LieLibraries shouldn't lie. That's not why they're called "lie-braries"...
The threadpool is an app-global resource, so you should leave the callers of your library to decide how and when they want to use it. Your library methods should not use the threadpool (Task.Run, Parallel.For, ...) internally...
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Six Essential Tips For Async - IntroductionAsync involves some new concepts. They're not difficult; just unfamiliar. Over the past year Lucian Wischik has been watching how people use async/await in C# and VB. This series distils out the three top async patterns and anti-patterns, and top three tips for writing your own async libraries.
Tips:...
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Tip 1: Async void is for top-level event-handlers onlyAsync Tip #1: Async void is for top-level event-handlers only, and event-like things. Don't use it elsewhere in your code.
Slides are available on Lucian's blog.
Async void is a "fire-and-forget" mechanism: the caller is unable to know when an async void has finished, and the caller...
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Tip 2: Distinguish CPU-Bound work from IO-bound workAsync Tip #2: It's crucial to distinguish CPU-bound work (should be done on threadpool) from IO-bound work (which needn't).
You can download slides for this talk from Lucian's blog.I remember reading an old Android dev blog post. It said: "1. A good practice in creating responsive applications... -
Tip 3: Wrap events up in Task-returning APIs and await themAsync Tip #3: You can wrap events up in Task-returning APIs and await them. This can dramatically simplify code.
Slides and source code are available on Lucian's blog.
This video introduces a new pattern for dealing with events: you can await them! Now why would you want to do that? Well, in...
| Forum | Thread | Replies | Latest activity |
|---|---|---|---|
| Coffeehouse | async and lock | 76 | Jun 19, 2014 at 9:56 AM |
| Coffeehouse | Why is the "async" keyword needed? | 31 | Nov 01, 2010 at 5:34 PM |
Staff
Here is a list of Channel 9 staff members.
What's New in Visual Basic 14
Nov 17, 2014 at 9:16 AM@LarHel, yes, all features work fine when down-targeting.
There's one corner of string interpolation to mention... we'll let you write
Dim x As FormattedString = $"hello {p.Age:0.00}" x.FormatString ' String with value "hello {0:0.00}" x.Args ' Object array with one element, p.AgeThis will only work if the "FormattedString" type is present. This will be built into .NET4.6, but it will also be available in a NuGet package for people targeting older versions of the framework. Similar to what we did with Microsoft.Bcl.Async
What's New In C# 6.0
Nov 15, 2014 at 5:25 PMIf you wish to enforce a team policy that no one is allowed to use ?. there's now a really easy way to do it. Look at Alex's video about "analyzers": http://channel9.msdn.com/Events/Visual-Studio/Connect-event-2014/714
It will take you about 30 minutes to write an analyzer that enforces the rule "no ?. is allowed". You can add the analyzer as a reference to your projects. This will give a compile-time error (both on dev machines and on your team build server) anytime anyone uses the ?. operator.
What's New In C# 6.0
Nov 15, 2014 at 10:30 AM@Kintar - I don't like videos either :) All of Mads' material is on the C#/VB project site here in a lot more depth - https://roslyn.codeplex.com/wikipage?title=Language%20Feature%20Status
Also we'll be putting up a blog post about the new features early next week - http://blogs.msdn.com/b/csharpfaq/
What's New in Visual Basic 14
Nov 13, 2014 at 2:10 PMClarification: two of the features mentioned "NameOf" and "String Interpolation" aren't yet in VS2015 Preview; they'll come along presently (prior to the final release of VS2015).
.NET 2015 & Managed Languages
Nov 13, 2014 at 11:18 AM@carlospinedag, I'm curious if you've tried the "IL Support" extension on the Visual Studio gallery? It's a third-party extension that people use to put IL directly into their VB/C# projects. Hasn't yet been updated for VS2015.
https://visualstudiogallery.msdn.microsoft.com/530dc77a-a9b0-43bf-9ae2-9498b0ec15da
Tip 4: Async Library Methods Shouldn't Lie
Feb 17, 2014 at 8:54 AM@Joao, thanks for the pointer. I think that MSDN page has poor guidance. I'll contact the authors of it.
Tip 4: Async Library Methods Shouldn't Lie
Feb 17, 2014 at 8:53 AM@squizfloats - You've got the right idea. This is a situation where the overall API design is forcing you to have an async signature, even though your method itself isn't async in its implementation.
Please watch the next video in the series. That discusses EXACTLY this case. Actually it discusses it in the guise of "MemoryStream". Obviously Stream has to have async APIs since most streams (disk, network, ...) are asynchronous in nature. But when you come to implement MemoryStream, it has no natural async implementation. And so it uses Task.FromResult exactly as you described.
The video talks about several useful micro-optimizations specifically for this case. Worth considering.
Creating Async Libraries That Are Modular, Reusable and Fast, in Microsoft Visual C# and Visual Basic
Jun 28, 2013 at 2:11 AMI uploaded the source code for this session here: http://blogs.msdn.com/b/lucian/archive/2013/06/28/talk-the-complete-async-three-talks-from-teched-europe-2013.aspx
Three Essential Tips for Using Async in Microsoft Visual C# and Visual Basic
Jun 28, 2013 at 2:11 AMI uploaded the source code for this session here: http://blogs.msdn.com/b/lucian/archive/2013/06/28/talk-the-complete-async-three-talks-from-teched-europe-2013.aspx
Easy Async for Windows Store Apps in Microsoft Visual C# and Microsoft Visual Basic
Jun 28, 2013 at 2:11 AMI uploaded the source code for this session here: http://blogs.msdn.com/b/lucian/archive/2013/06/28/talk-the-complete-async-three-talks-from-teched-europe-2013.aspx
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