Sharing code between Windows Store and Windows Phone apps. Presented by Laurent Duveau on February 9th during a Montreal .NET Community special event. Parts of the presentation were taken from existing Microsoft presentations.

1. 2013-02-09
Laurent Duveau
Developing for both
Windows Phone 8
and Windows 8
ldex.ca @laurentduveau
Laurent Duveau
Windows 8 Instructor
MVP / MCT / RD

2. Agenda
• Building for Windows Devices
• Consistent Experience
• Tiles, Notifications, Animations
• Differences
• Screen Sizes, Controls, Lifecycle
• Minimizing Development
• Reuse
• Portable Class Library
• Sharing Code

3. Some Key Differences
It’s important to design for the platform differences as well as similarities
Screen Size Controls Lifecycle
Windows Phone Windows Phone Windows Phone
800x480, 1280x720, 1280x768 Panorama, Pivot, ListPicker Launched from start/apps list.
Portrait, Landscape LongListSelector Tombstones apps
Windows Windows Windows
1024x768  GridView, ListView, Semantic Resumes existing apps
Portrait, Landscape, Snapped Zoom, FlipView No tombstoning

4. Strategies for sharing in a XAML app
• Separate UI from app logic (Model-View-ViewModel)
• Share portable .NET code in Portable Class Library
• Use common Windows Runtime API (Add as Link)
• Complete with platform-specific code as necessary

5. Separate UI from app logic

6. Model-View-ViewModel (MVVM)

7. Cross-platform app architecture

8. Minimizing Development

9. Reuse
Reusing pre-built components or libraries
Portable Class Library
• Managed Code
• Reusable library
• One codebase with no conditional compilation

10. Demo
Portable Class Libraries

11. Sharing Code
Reusing code by including code files in multiple projects
Share Code Files
•Use Add as Link to include same files in multiple projects
•Change once, Change everywhere
•What to do where platforms don’t match?
•#if conditional blocks
•Inheritance
•Partial Classes and Methods

12. Sharing Code: #if Conditional Blocks
• Enable/Disable lines or chunks of code based on compilation platform
• Existing compilation constants
• NETFX_CORE Windows 8
• WINDOWS_PHONE Windows Phone 8
• Useful for when there are subtle differences in syntax or methods
• Can make code unreadable…

13. Sharing Code: #if Conditional Blocks
#if NETFX_CORE
using Windows.UI.Xaml.Media.Imaging;
#else
using System.Windows.Media.Imaging;
#endif

14. Sharing Code: #if Conditional Blocks
public object Convert(object value, Type targetType, object parameter,
#if !NETFX_CORE
CultureInfo culture
#else
string language
#endif
)

15. Sharing Code: Partial Classes & Methods
• Shared functionality in one code file eg: DataSource.cs
• Platform specific code in additional code file eg: DataSource.WP8.cs
• Classes are marked as partial and compiled into a single class
• Separates platform specific features
• Can use partial methods as a mechanism to separate out platform specific logic

16. Sharing Code: Partial Classes & Methods
/// <summary>
/// DataSource.cs
/// </summary>
public partial class DataSource:IDataSource {
public async Task<IEnumerable<IFolder>> RetrieveFolders(IFolder root) {
... // other logic
var folders = await LoadFolders(root);
... // other logic
return folders
}
}
/// <summary>
/// DataSource.WP8.cs
/// </summary>
public partial class DataSource {
private async Task<IEnumerable<IFolder>> LoadFolders(IFolder root) {
...
}
}

17. Demo
Sharing Code