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4.Open source Cross platform Open language API “Roslyn” Cross IDE Open design Open to change “New direction” on the Great Wall 

5.from c in customers customers where c.City == "Beijing" .Where(c => c.City == "Beijing") select c.Name; .Select(c => c.Name); from c in customers customers where c.City == "Beijing" .Where(c => c.City == "Beijing") from o in c.Orders .SelectMany(c => c.Orders, (c, o) => new { c, o }) select (c.Name, o.Price); .Select(p => (p.c.Name, p.o.Price)); 

6.void PlaySongs(int[] ids) { foreach (var id in ids) { try { var data = service.GetEncodedData(id); var song = Decode(data); Play(song); } catch (Exception e) { /* just skip the song */ } } } 

7.Task PlaySongsAsync(int[] ids) { foreach (var id in ids) { try { var data = service.GetEncodedData(id); var song = Decode(data); Play(song); } catch (Exception e) { /* just skip the song */ } } } 

8.async Task PlaySongsAsync(int[] ids) { foreach (var id in ids) { try { var data = service.GetEncodedData(id); var song = Decode(data); Play(song); } catch (Exception e) { /* just skip the song */ } } } 

9.async Task PlaySongsAsync(int[] ids) { foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = Decode(data); Play(song); } catch (Exception e) { /* just skip the song */ } } } 

10.async Task PlaySongsAsync(int[] ids) { foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = Decode(data); await PlayAsync(song); } catch (Exception e) { /* just skip the song */ } } } 

11.async Task PlaySongsAsync(int[] ids) { foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = await Task.Run(() => Decode(data)); await PlayAsync(song); } catch (Exception e) { /* just skip the song */ } } } 

12.async Task PlaySongsAsync(int[] ids) { Task currentlyPlaying = Task.FromResult(true); foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = await Task.Run(() => Decode(data)); await PlayAsync(song); } catch (Exception e) { /* just skip the song */ } } } 

13.async Task PlaySongsAsync(int[] ids) { Task currentlyPlaying = Task.FromResult(true); foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = await Task.Run(() => Decode(data)); await currentlyPlaying; currentlyPlaying = PlayAsync(song); } catch (Exception e) { /* just skip the song */ } } } 

14.async Task PlaySongsAsync(int[] ids) { Task currentlyPlaying = Task.FromResult(true); foreach (var id in ids) { try { var data = await service.GetEncodedDataAsync(id); var song = await Task.Run(() => Decode(data)); await currentlyPlaying; currentlyPlaying = PlayAsync(song); } catch (Exception e) { /* just skip the song */ } } try { await currentlyPlaying; } catch (Exception e) { } } 

15. Evolve... a little a lot Stagnation C# 

16. C# 7 C# 6 Work with Eliminate data C# 5 ceremony C# 4 Async Dynamic, C# 3 Concurrency Queries, C# 2 Lambdas C# 1 Generics Hello World 

17.East gate to Beihai Park 

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