What's New in C#6

Dissatisfied that C#5 only added async and await? In C#6 you now have a lot more features! In this session we'll cover what these features are (e.g. nameof and string interpolation) and how they work in detail so you'll know when to use them effectively in your new .NET projects. You'll also see where C# is going with proposed features for C#7.

Transcript

1. What’s New in C#6 Jason Bock Practice Lead
2. »http://www.magenic.com »http://www.jasonbock.net »https://www.twitter.com/jasonbock »https://www.github.com/jasonbock »jasonb@magenic.com Personal Info
3. https://github.com/JasonBock/ WhatsNewInCSharp6 http://www.slideshare.net/jasonbock/ whats-new-in-c6 Downloads
4. »Language Evolution »C#6 Features »Future Directions Overview Remember… https://github.com/JasonBock/ WhatsNewInCSharp6 http://www.slideshare.net/jasonbock/whats-new-in-c6
5. Language Evolution Est. 2002
6. »Classes (and Interfaces) and Structs »Common Control Flow (switch, if/else, etc.) »Exception Handling (try/catch/finally) »Visibility (public/protected/private) »Delegates and Events Language Evolution Version 1
7. »Generics »Iterators and Yield »Static and Partial Classes »Nullable Types Language Evolution Version 2
8. »LINQ › Type Inference › Object and Collection Initializers › Anonymous Types › Expression Trees › Extension Methods Language Evolution Version 3
9. »Co- and Contravariance »Dynamic »Named and Optional Arguments Language Evolution Version 4
10. »Async/Await Language Evolution Version 5
11. Language Evolution http://static.hdw.eweb4.com/media/wallpapers_1920x1080/fantasy/1/1/dark-tower-fantasy-hd-wallpaper- 1920x1080-5771.jpg
12. Language Evolution http://www.dotnetfoundation.org/ The .NET Foundation is an independent organization to foster open development and collaboration around the growing collection of open source technologies for .NET
13. Language Evolution https://github.com/dotnet/roslyn
14. »Auto-property initializers »Getter-only auto-properties »Ctor assignment to getter-only autoprops »Using static members »Indexer initializer »Await in catch/finally »Exception filters Language Evolution Version 6 https://github.com/dotnet/roslyn/wiki/Languages-features-in-C%23-6-and-VB-14 »Expression-bodied members »Null propagation »String interpolation »nameof operator »#pragma »Extension Add in collection initializers »Improved overload resolution
15. »Auto-property initializers › Makes it easy to set a property to an initial value › public property FirstName { get; set; } = "Jason"; »Getter-only auto-properties › If you want a property to be truly “read-only” – i.e. a private setter and the backing field is marked as readonly… › public property FirstName { get; } = "Jason"; »Ctor assignment to getter-only autoprops › You can also do this with getter-only autoprops › public Person { this.FirstName = "Jason"; } C#6 Features - Properties
16. »Using static members › Static members always require the name of the class for resolution › using “using static” removes that › E.g. - using static System.Math; › This also “imports” all the extension methods as well »Expression-bodied members › If a method is short – e.g. one line of code – you can now define without the curly braces › E.g. public int Double(int x) => Add(x, x); C#6 Features - Functions
17. »Null conditional › Enables safe access to members in deep object graphs › E.g. - parent.Child?.ToString() »String interpolation › Allows you to define the “holes” directly in a formattable string › E.g. - $"{this.FirstName} {this.LastName}" »nameof › Provides a way to get the name of a member in code › Removes the need for magic string usage › Useful for ArgumentNullException, property changed implementations, WeakEventManager, etc. C#6 Features – Syntax
18. »Await in catch/finally › Before C#6, you couldn’t await a method in a catch or finally block. Now you can! › E.g. – try { /* ... */ } catch(MyException) { await SomeCall(); } »Exception filters › VB has always had the ability to filter exceptions – that is, only enter a catch block if some condition is true. Now C#6 has it! › E.g. – catch(MyException) when (this.HandleIt) { /* ... */ } C#6 Features - Exceptions
19. »Indexer initializer › Can be used for dictionaries or any object with an indexer › E.g. – var things = new Things { [0] = "Tesla" }; »#pragma › Now works with an identifier as well as an integer, which maps to C# errors › E.g. these are the same − #pragma warning disable 219 − #pragma warning disable CS0219 › Potentially useful for analyzer errors to disable/enable rather than using SuppressMessageAttribute everywhere C#6 Features - Miscellaneous
20. Future Directions https://dialectline.files.wordpress.com/2012/04/crystal_ball1.jpg
21. Future Directions https://github.com/dotnet/roslyn/issues?utf8=%E2%9C%93&q=label%3A%22Up+For+Grabs%22+
22. Future Directions https://github.com/dotnet/roslyn/labels/Design%20Notes
23. »My choices/ideas › Generic attributes: [MyMetadata<string>] › Fault blocks: try { … } fault { … } › Metaprogramming: [Disposable] public class MyClass › Reactive programming Future Directions
24. »C#7 (maybe) › Ref locals and returns › Local methods › Slices › Metaprogramming › Tuples (not just the Tuple type) › Pattern matching › Non-nullable types Future Directions
25. What’s New in C#6 Jason Bock Practice Lead Remember… • https://github.com/JasonBock/WhatsNewInCSharp6 • http://www.slideshare.net/jasonbock/whats-new-in-c6 • References in the notes on this slide