3. RuntimeLibraries Languages Tools.NET

4. First, a look at.NET 4.5 Client & Device Async – for UI responsiveness Windows Store apps -- WinRT Windows Phone apps.NET CF 3.9 Web & Cloud Async – for server scaling ASP.NET MVC4 ASP.NET Web API ASP.NET Web Pages Entity Framework Code-First WebSockets SignalR Windows Azure Cloud Services 4.5 Support Windows Azure Web Sites Fundamentals.NET Async (async + await) Many new async APIs WinRT interop Multi-core JIT MPGO – NGEN hot/cold splitting Performance improvements Reboot and reliability improvements to setup Support Windows RT GC Background GC LOH heap balancing LOH fragmentation reduction GC low latency mode GC awareness of NUMA and >64 processors >2GB arrays (or objects) Libraries Portable libraries update.NET Core Profile (Windows 8) Extension methods for WinRT streams and async NuGet Immutable collections Async for.NET 4 HttpClient for Portable.NET 4.5.NET 4.5 is installed on 100+ million machines!

5. .NET 4.5.1 in A Nutshell

10. 64-bit Edit and Continue is finally here! Number 9 all time requested feature on UserVoice! Works exactly the same as for 32-bit applications Client (WPF, WinForms, etc.), Store and ASP.NET WAP projects are supported For WAP projects, need to enable Edit & Continue in Project Properties

13. Method Return Value Inspection Now available for.NET! Access via Autos window or in the Immediate window ($ReturnValue) Can expand return value in the debugger

14. Async Debugging Improvements Common question: How did I get here? Supported for Store Apps, Web apps, Desktop apps in W8.1 Enhancements to the Call Stack and Tasks window Visual Studio 2012

15. Windows Store Development Improvements Convert System.IO.Stream to IRandomAccessStream Allows much easier interop with existing.NET code Better exception support for WinRT APIs System.Exception.Message System.Exception.StackTrace WinRT type system enhancements Nullable value types in WinRT structs 64-bit Edit and Continue support Managed Return Value Inspection support Async debugging enhancedments

16. Convert Stream to IRandomAccessStream From MSDN Forums… In.NET 4.5.1: System.IO.WindowsRuntimeStreamExtensions.AsRandomAccessStream(Stream stream)

17. Rich exception interop support for WinRT APIs In Windows 8, error propagation for WinRT APIs is through HRESULT Important Exception information is lost unless a debugger is attached In Windows 8.1, additional error information is available via System.Exception properties: Message StackTrace Additional exception details from a C++ WinRT Component

18. WinRT Type System Enhancements Support Nullable value types in WinRT structs ' is not a valid Windows Runtime field type.

19. EF/ADO.NET Connection Resiliency Provide reliable connection to Azure DB Automatically retry/reconnect broken connection Provides great experience for connected devices It Just Works! No code or configuration changes other than installing.NET 4.5.1

21. Early Results from our Performance Lab

24. On-demand Large Object Heap Compaction Refresher Large objects (>85000 bytes) treated specially Very expensive to compact Collected with Gen 2 In.NET 4.5.1, you can now compact the Large Object Heap (LOH) to address heap fragmentation The LOH mode is part of GCSettings:

25. On-demand Large Object Heap Compaction Two ways to use GC LOH API: 1.Compact LOH right away 2.Compact LOH with the next full blocking GC

27. Multi-Core JIT Improvements Performance data from our test labs Minimize application startup time on multi- core CPUs Now supported for ASP.NET web sites Enabled automatically for ASP.NET apps 15% improvement for cold startup

28. Consistent Performance Before & After Servicing.NET Servicing.NET Framework for 1B+ PCs is a very BIG deal! Today, servicing the.NET Framework can lead to degradation in app performance directly afterwards This is due to core.NET assemblies being JIT-compiled for a period of time after servicing In Windows 8.1, app performance remains consistent even after servicing the.NET Framework Results in much better user experience and better battery life on tablets

30. Our goal is to keep the existing values of the.NET Framework while allowing for more agility and innovation Existing Values Great discoverability (all in in place) Known quality, maturity and compatibility level A single license and support policy Centralized patching for security issues *PLUS* New Values Faster release cadence with a tighter customer feedback loop Less friction with using features across.NET platforms

31. .NET (“in box”) System Composition TPL Dataflow Http Client Async Immutable Collections

33. Visual Studio 20[10,12]

34. What’s New in.NET Development

35. @dotnet dotnet BlogE-mail UserVoiceMSDN Forums

36. 2-303: What’s New in.NET Development