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CSharp 5 Async
This document discusses asynchronous programming in C# 5.0 using the async and await keywords. It provides an overview of asynchronous programming models that preceded async/await such as Asynchronous Programming Model and Event-based Asynchronous Pattern. It describes how async methods allow code to appear synchronous while tasks execute asynchronously without blocking threads. The await keyword signs up the rest of the method as a continuation when awaiting tasks. Async methods return Task, Task<T>, or void and conventions suggest naming async methods with a suffix of "Async".
CSharp 5 Async
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- 2. Valdis Iljuconoks Technical Fellow,Software Architect Microsoft MVP Geta AS, Viiar Consulting valdis.iljuconoks@dotnet.lv http://dotnet.lv/blogs/vi @tech_fellow
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- 6. concurrency & asynchrony
- 7. sequential concurrent parallel asynchronous
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- 10. Asynchronous Programming Model(APM) Event-based Asynchronous Pattern (EAP)
- 11. C# 5.0 C# 4.0 Async C# 3.0 Dynamics Language C# 2.0 Integrated Generics Query C# 1.0 Component on a Managed Runtime
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- 13. ‘Task’ is representationof ongoing work
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- 17. referred as asyncmethod
- 18. modifier (async) appliedto • a method • a lambda expression • an anonymous method
- 19. keyword (await) usedin • body of an immediately enclosing method • lambda expression • anonymous method
- 20. await NOT usedin • synchronous function • query expression • catch or finally block • in lock statement • unsafe context
- 21. absence of anoperator cause a compiler warning
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- 23. Async methods areintended to be non- blocking operations
- 24. await expression doesnot block the current thread while the awaited task is running
- 25. expression signs upthe rest of the method as a continuation
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- 27. returns control tothe caller of the async method.
- 28. Method executes synchronously till first ‘await’.
- 29. Async methods don'trequire multithreading
- 30. async method doesn'trun on its own thread
- 31. method runs onthe current synchronization context.
- 32. Task based asyncpattern
- 33. Async method returntypes • void • Task • Task<TResult>
- 34. async void FireAndForget() { await t; } FireAndForget();
- 35. async Task JustSignalCompletionAsync() { return; } await JustSignalCompletionAsync();
- 36. async Task<int> GetResultsAsync() { return 5; } var r = await GetResultsAsync();
- 37. Naming conventions • Byconvention, the suffix "Async" is added • Async methods that return void are discouraged • Exceptions to the naming convention (e.g. event handlers)
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- 39. Valdis Iljuconoks Technical Fellow,Software Architect Microsoft MVP Geta AS, Viiar Consulting valdis.iljuconoks@dotnet.lv http://dotnet.lv/blogs/vi @tech_fellow
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