WinRT Holy COw

www.buildwindows.com

WinRT Holy Cow

Eugene ZharkovSilverlight MVP


Windows has always provided compelling capabilities for developers to build upon

Windows has not always made it straightforward for you to use

these capabilities from C# or VB

[DllImport("avicap32.dll", EntryPoint="capCreateCaptureWindow")]static extern int capCreateCaptureWindow( string lpszWindowName, int dwStyle, int X, int Y, int nWidth, int nHeight, int hwndParent, int nID);

[DllImport("avicap32.dll")] static extern bool capGetDriverDescription( int wDriverIndex, [MarshalAs(UnmanagedType.LPTStr)] ref string lpszName, int cbName, [MarshalAs(UnmanagedType.LPTStr)] ref string lpszVer, int cbVer);

// more and more of the same

The C# code you have to write today…


Traditional Windows API

Your Managed Code

Manually Generated

Interop Code

The C# code you get to write on Windows 8

using Windows.Media.Capture;

var ui = new CameraCaptureUI();ui.PhotoSettings.CroppedAspectRatio = new Size(4, 3);

var file = await ui.CaptureFileAsync(CameraCaptureUIMode.Photo);

if (file != null) { var bitmap = new BitmapImage() ; bitmap.SetSource(await file.OpenAsync(FileAccessMode.Read)); Photo.Source = bitmap;}


Windows Runtime Architecture

Windows Metadata & Namespace

Language Projection

Windows Core

Windows Runtime Core

XAML Storage …Network

UI Pickers MediaControls

Metro style app

Runtime Broker

Language Support (CLR, WinJS, CRT)

Web Host (HTML, CSS, JavaScript))


Your Managed Code

Windows Runtime

Windows 8 API


You already have the skills to build Metro style apps

with C# and VB


Agenda

• The relationship between .NET and the Windows Runtime

• Using Windows Runtime APIs from C# and Visual Basic

• Building Window Runtime Components in C# and Visual Basic

C# and Visual Basic influencedthe Windows Runtime


Windows Runtime is designed to be used from object-oriented

languages like C# and Visual Basic


Windows Runtime metadata files use an updated version of .NET’s

metadata format


Viewing Windows Metadata Files

demo


Windows Runtime includes a XAML based framework for Metro style

apps


Many of the Windows Runtime design guidelines

came from the .NET design guidelines


Windows Runtime was expressly designed

to work well with C# and Visual Basic

Using the Windows Runtime feels natural and

familiar from C# and Visual Basic


Using the Windows Runtime from C#

demo

Most WinRT types map directly to C#/VB


var file = await ui.CaptureFileAsync(CameraCaptureUIMode.Photo);

if (file != null) { var bitmap = new BitmapImage() ; bitmap.SetSource(await file.OpenAsync(FileAccessMode.Read)); Photo.Source = bitmap;}


Primitives(strings, numbers, etc)

Interfaces

Enums

Structs

Static Members

Properties

EventsDelegates

Classes

Constructors

Methods

Almost everything maps directly between

the Windows Runtime and .NET


Most differences between Windows Runtime and

.NET are hidden from the managed developer

Exceptions from HRESULTs

try{


}catch (Exception e){ //Exception handling code}

ComException

Calling WinRT Async Operation from C#

var picker = new FileOpenPicker();picker.FileTypeFilter.Add("*");var files = await picker.PickMultipleFilesAsync();foreach (var file in files){ lbFiles.Items.Add(file.FileName);}

PickMultipleFilesOperation PickMultipleFilesAsync();

public sealed class PickMultipleFilesOperation : IAsyncOperation<IReadOnlyList<StorageFile>>, IAsyncInfo

Accessing a WinRT Collection from C#

var picker = new FileOpenPicker();picker.FileTypeFilter.Add("*");var files = await picker.PickMultipleFilesAsync();foreach (StorageFile file in files){ lbFiles.Items.Add(file.FileName);}

System.Collections.Generic.IReadOnlyList <Windows.Storage.StorageFile>

Accessing a WinRT Collection from C#

var picker = new FileOpenPicker();picker.FileTypeFilter.Add("*");var files = await picker.PickMultipleFilesAsync();foreach (StorageFile file in files){ lbFiles.Items.Add(file.FileName);}

System.Collections.Generic.IReadOnlyList <Windows.Storage.StorageFile>

Windows.Foundation.Collections.IVectorView <Windows.Storage.StorageFile>


IIterable<T> ↔ IEnumerable<T>

IVector<T> ↔ IList<T>

IVectorView<T> ↔ IReadOnlyList<T>

IMap<K,V> ↔ IDictionary<K,V>

IMapView<K,V> ↔ IReadOnlyDictionary<K,V>

.NET automatically maps collection interfaces to their Windows

Runtime equivalent


A few places use extension methods to bridge between Windows Runtime and managed code

Streams Code Sample

FileOpenPicker picker = new FileOpenPicker();picker.FileTypeFilter.Add("*");

StorageFile file = await picker.PickSingleFileAsync();

Windows.Storage.Streams.IInputStream inputStream = await file.OpenForReadAsync();

System.IO.Stream stream = inputStream.AsStream();System.IO.StreamReader reader = new StreamReader(stream);

string contents = reader.ReadToEnd();

IBuffer Code Sample

internal async void ProtectBytes(byte[] data, BinaryWriter output){ DataProtectionProvider dpp = new DataProtectionProvider();

IBuffer result = await dpp.ProtectAsync(data.AsBuffer()); byte[] protectedData; int start = 0; if (result.TryGetUnderlyingData(out protectedData, out start)) output.Write(protectedData); else throw new InvalidOperationException();}

You can write your own Windows Runtime components

in C# or Visual Basic


You should build a Windows Runtime component when you want

your code to be used fromJS, C++, C# and VB

Traditional COM in Managed Code

[ComVisible(true), Guid("06D7901C-9045-4241-B8A0-39A1AC0F8618")]public interface IWindowsApiSample{ string HelloWorld();}

[ComVisible(true), [ClassInterface(ClassInterfaceType.None)] [ComDefaultInterface(typeof(IWindowsApiSample))]public class WindowsApiSample : IWindowsApiSample{ public string HelloWorld() { return "Hello, World!"; }}

Windows Runtime in managed code Sample

public sealed class MyClassLibrary{ public string HelloWorld() { return "Hello, World!"; }}


By adhering to a few simple rules, you can build

a managed Windows Runtime component

that projects into C++ or JavaScript


Only the public types and members

in your managed Windows Runtime component project need to follow

the simple rules


API signatures must only use Windows Runtime types

Inheritance can only be used for XAML controls,

all other types must be sealedOnly supports system provided generic types

Structs can only have public data fields

public sealed class ManagedLibrary{ public List<int> GetNumbers() { List<int> numbers = new List<int>(); numbers.AddRange(new int[] {0,1,1,2,3}); return numbers; }}

Authoring Collection Code

public sealed class ManagedLibrary{ public IList<int> GetNumbers() { List<int> numbers = new List<int>(); numbers.AddRange(new int[] {0,1,1,2,3}); return numbers; }}

Authoring Collection Code

private async Task<string> GetTweetTaskAsync(){ string url = "http://api.twitter.com/1/statuses/" + "user_timeline.xml?screen_name=bldwin"; var http = new HttpClient(); var resp = await http.GetAsync(url); var xml = XDocument.Load(resp.Content.ContentReadStream); var str = xml.Descendants("text") .Select(x => x.Value).First(); return str;}

Authoring Managed Async Method

Authoring Windows Runtime Async Method

public IAsyncOperation<string> GetTweetAsync(){ return AsyncInfoFactory.Create( () => this.GetTweetTaskAsync());}


Visual Studio has built-in support for managed

Windows Runtime component projects


Building Windows Runtime Components in C#

demo


You already have the skills to build Metro style apps

with C# and VB

Influenced by C# and VB

Feels natural and familiar from C# and Visual Basic

Build your own managed Windows Runtime components


• [email protected]

• @2j2e

thank you

WinRT Holy COw

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