1. Introduction to
Windows Runtime (WinRT)
Raffaele Rialdi
@raffaeler
raffaeler@vevy.com http://www.iamraf.net
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2. Mobile &
ITCamp 2012 sponsors Development
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3. Mobile &
Agenda Development
• You already heard about
– «Tailored User eXperience»
• Inspiring confidence, Fast and fluid, Touch-first, Immersive,
Engaging and Alive, Connected
– Why current applications does not fit the new market
• We will dig into:
– What is the Windows Runtime (WinRT)
– Why Win8 is not a simple UI restyling
– What are the pillars (from a developer point of view)
– How can you get it to the max
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4. Mobile &
OO vs not-OO Development
• Procedural languages have no implicit lifetime
concept
– malloc free, CreateFile  CloseHandle, …
• In .NET, Dispose pattern is a partial solution
– It's not automatic
– Can lead to resources leak
• Requires PInvoke for accessing C-Libraries
• Communication between processes is done via IPC
and not between components
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5. Mobile &
Windows Runtime Architecture Development
Metro apps Desktop apps
Win MFC
XAML DirectX HTML WPF SL
form
HTML
DX
Language Projections .NET / Js / C++
.NET / Js / C++
Filtered access BCL / libraries
to WinRT
Windows Runtime APIs and Services
UI Controls Storage Media
Win32 Windows Win32
Metadata XAML Pickers Network …
Runtime Broker
Windows Runtime Core
Windows Kernel Services
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6. Mobile &
What is the Windows Runtime Development
• It's the evolution of Component Object
Model (COM)
– Easier
– Totally different Type System
– Same metadata of the .NET Fx (ECMA-335)
• WinRT and CLR talks the same "language"
• No marshalling gotchas
• It's not a replacement for the CLR
• CLR is required for managed languages
infrastructure
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7. Mobile &
Reference Count VS Garbage Collector Development
Root Root
A B A B
Parent
Parent Parent
• Circular references
• GC finds can find them as it freeze the app and search the roots
• Reference Count is autonomous and it can't
• In the new C++11 standard we have weak references
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8. Mobile &
WinRT Type System Development
• Basic types
- bool, integers, floats, enum, guid, type, object
• Strings
- binary compatibile with .NET (string) and C++ STL (wstring)
- are immutable
- are value-types (non-nullable)
• There are Reference Types
- All types that implement WinRT interfaces
• There are Value Types
- All the others … for example arrays and structures
- Structures can't declare reference (deep/shallow copy problem)
• "Complex" types
- Vector (collection) and Map (dictionary)
- Vector<T> implements IObservableVector<T> that is mapped
to INotifyCollectionChanged
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9. Mobile &
Language Projections Development
•Projections map WinRT types to the projected language
• Different casing standards
- Javascript (camelCase), C++ and .NET (PascalCase)
• Developers need to understand edge-cases
- Javascript standard only support IEEE-754 (floats).
This means the max integer is 53 bit maximum
• Few types are defined both in WinRT and .NET
- They are treated as 'special' and seen as equivalent
- INotifyPropertyChanged, INotifyCollectionChanged, …
• Some .NET types cannot be mapped transparently
- Streams, Buffers, Tasks are mapped via extension methods
• I expect third party projections too
- Java?, Python?, D language?, Delphi?, …
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10. Mobile &
Application Activation Development
Explorer.exe
Activate RPCSS
Activation
System
Application.exe
DCOM Class
Launch Catalog
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11. Mobile &
Contracts : «XXI century's clipboard» Development
• A standard way to "talk" to other Apps or OS services
• A sort of publisher / subscriber pattern
• Main Contracts available:
• Search, Share, Protocol, PlayTo, App to App picking
• WinRT activate Apps that expose Contracts
• Running Apps is done via Launch Contract
• Tiles are NOT shortcuts!
• Apps use the Manifest to opt-in for Contracts
• They receive parameters in the activation method
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12. Mobile &
Asynchronous by design Development
Problem: Apps should never block UI thread
Solution: API that may take more than 50ms are only async
• Special objects wraps Asynchronous Operations
• In WinRT they implement IAsyncOperation<T>
• AsTask extension method is used to convert it to a
Task<T>
• In .NET these objects are Task<T>
• AsAsyncOperation extension method to obtain an
IAsyncOperation<T>
• C# 5.0 have new async/await keywords
• Javascript and C++ can use "promises" pattern
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13. Mobile &
Application lifecycle Development
Process Suspend
App in Process Low App
is Active in Suspended Memory is
state state
Activated (system) closed
Resume
• Suspension happens after ~5s the App is not visible
• Suspension message is used to save App state
• Resume happens when user switch to the App
• Typically used to refresh data from sensors, WS, …
•There is no notification for the close transition
• App state is already saved during suspension
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14. Mobile &
The sandbox Development
Application Package
Application
code Manifest Marketplace
Security Broker Proxy
WinRT Libraries
Win32 White-listed
Windows Kernel Services
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15. Mobile &
Developing with WinRT Development
• XAML UI for .NET and C++
• XAML / DirectX can share surfaces
• DirectX inside a XAML control
• Large virtual DirectX surface in conjunction with XAML
• High Performance DirectX drawing, XAML overlapped
• Custom WinRT components are easy to write
• i.e. exposing C# or C++ code to Javascript or vice-versa
• Custom components are private to the App (no RegSvr32)
• Cross language calls are cheap
• No more P-Invokes!
• As fast as a vtable call
• Desktop Apps can use a WinRT APIs subset
• CLR have an additional weapon: "Portable Class Library"
• A DLL with code that run on Metro, desktop, SL, …
• As it's IL code, it runs as 32 or 64 bits as well
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16. Mobile &
Metro profile for .NET development Development
Metro profile was a good opportunity to clean BCL
• Removed: Xml DOM, WebClient, Threads, …
• Moved Reflection in System.Reflection
• GetTypeInfo extension method to access reflection classes
Metro Fx 4.5 WP7
# assemblies 15 120 22
# namespaces 60 400 88
# types ~1'000 ~14'000 ~2'000
# members ~10'000 ~110'000 ~14'000
• What else is not in the Metro profile?
• APIs that are already in WinRT (Storage, Sockets, Network, etc.)
• Server libraries like WCF, Asp.net, …
• APIs that could bypass the sandbox
• System.Data, Remoting, AppDomain, Private Reflection, …
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17. Mobile &
Developer thoughts Development
• No need to elevate (UAC) a Metro App
• Admin Apps will run in the old desktop
• Storage
• Apps can access only locations specified by manifest
• Users can pick (via UI) a file that is stored elsewhere
• No local db APIs at the moment
• Media and Sensors
• Easy access to cameras, accelerometer, …
• Require user consent (requested via manifest)
• Network
• Great library to ease oAuth authentication
• Flexible HttpClient replace WebClient
• Websockets support
• Dig into the APIs and discover it by yourself!
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18. Mobile &
Takeaways Development
• WinRT is a great step in Windows evolution
• Exposes native OS services in a pure OOP way
• Closes the gap between managed and native
languages
• Developers can use their current knowledge to
create Apps from small devices to classic PCs
• Marketplace is an opportunity for developers
and a sweet experience for end-users
• Think about performance/battery issues
• It's Framework.NET best friend
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19. Mobile &
Tools for WinRT Development
• WinRT.codeplex.com
• Debug Activation, WRL project template, ... (more to come)
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20. Q&A
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