Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Correcting Common Async/Await Mistakes in .NET

112 views

Published on

Did you know that the .NET compiler turns our async methods into classes? And that .NET adds a try/catch block to each of these classes, potentially hiding thrown exceptions? It's true! In this session, we will learn how to best use async/await in C# by analyzing how .NET compiles our async code. Join me as we take an existing app and optimize its async code together, showing off performance gains, better exception handling, improved run-time speed, and smaller app size!

Published in: Technology
  • Be the first to comment

Correcting Common Async/Await Mistakes in .NET

  1. 1. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  2. 2. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); }
  3. 3. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } Thread 1
  4. 4. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } Thread 2* *Can be any thread other than Thread 1 e.g. Thread 32
  5. 5. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } Thread 1
  6. 6. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); }
  7. 7. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } private sealed class <ReadDataFromUrl>d_1 : IAsyncStateMachine
  8. 8. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } private string <data>5_3; private byte[] <result>5_2; private WebClient <wc>5_1; public string url;
  9. 9. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ async Task ReadDataFromUrl(string url) { WebClient wc = new WebClient(); byte[] result = await wc.DownloadDataTaskAsync(url); string data = Encoding.ASCII.GetString(result); LoadData(data); } private void MoveNext();
  10. 10. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ public void MoveNext() { uint num = (uint)this.$PC; this.$PC = -1; try { switch (num) { case 0: this.<wc>__0 = new WebClient(); this.$awaiter0 = this.<wc>__0.DownloadDataTaskAsync(this.url).GetAwaiter(); this.$PC = 1; ... return; break; case 1: this.<result>__1 = this.$awaiter0.GetResult(); this.<data>__2 = Encoding.ASCII.GetString(this.<result>__1); this.$this.LoadData(this.<data>__2); break; default: return; } } catch (Exception exception) { ... } this.$PC = -1; this.$builder.SetResult(); }
  11. 11. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ public void MoveNext() { uint num = (uint)this.$PC; this.$PC = -1; try { switch (num) { case 0: this.<wc>__0 = new WebClient(); this.$awaiter0 = this.<wc>__0.DownloadDataTaskAsync(this.url).GetAwaiter(); this.$PC = 1; ... return; break; case 1: this.<result>__1 = this.$awaiter0.GetResult(); this.<data>__2 = Encoding.ASCII.GetString(this.<result>__1); this.$this.LoadData(this.<data>__2); break; default: return; } } catch (Exception exception) { ... } this.$PC = -1; this.$builder.SetResult(); } case 0: this.<wc>__0 = new WebClient(); this.$awaiter0 = this.<wc>__0.DownloadDataTaskAsync(this.url).GetAwaiter(); this.$PC = 1; ... return;
  12. 12. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ public void MoveNext() { uint num = (uint)this.$PC; this.$PC = -1; try { switch (num) { case 0: this.<wc>__0 = new WebClient(); this.$awaiter0 = this.<wc>__0.DownloadDataTaskAsync(this.url).GetAwaiter(); this.$PC = 1; ... return; break; case 1: this.<result>__1 = this.$awaiter0.GetResult(); this.<data>__2 = Encoding.ASCII.GetString(this.<result>__1); this.$this.LoadData(this.<data>__2); break; default: return; } } catch (Exception exception) { ... } this.$PC = -1; this.$builder.SetResult(); } case 1: this.<result>__1 = this.$awaiter0.GetResult(); this.<data>__2 = Encoding.ASCII.GetString(this.<result>__1); this.$this.LoadData(this.<data>__2); break;
  13. 13. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/ public void MoveNext() { uint num = (uint)this.$PC; this.$PC = -1; try { switch (num) { case 0: this.<wc>__0 = new WebClient(); this.$awaiter0 = this.<wc>__0.DownloadDataTaskAsync(this.url).GetAwaiter(); this.$PC = 1; ... return; break; case 1: this.<result>__1 = this.$awaiter0.GetResult(); this.<data>__2 = Encoding.ASCII.GetString(this.<result>__1); this.$this.LoadData(this.<data>__2); break; default: return; } } catch (Exception exception) { ... } this.$PC = -1; this.$builder.SetResult(); } try { catch (Exception exception) { . . . }
  14. 14. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait
  15. 15. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait
  16. 16. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  17. 17. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  18. 18. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  19. 19. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  20. 20. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  21. 21. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait/
  22. 22. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait https://codetraveler.io/CodeMotion-AsyncAwait/
  23. 23. @TheCodeTraveler https://codetraveler.io/CodeMotion-AsyncAwait https://codetraveler.io/CodeMotion-AsyncAwait/

×