C#6 Explained & MvvmCross!

Transcript

1. C#6 & MvvmCross Martijn van Dijk @mhvdijk mhvdijk@gmail.com github.com/martijn00 speakerdeck.com/martijn00
2. Agenda ▪ C# 6 explained ▪ What is MvvmCross
3. Do you C# ??? Otherwise you would need some glasses
4. C# 6 ▪ C# 6 is the version of C# that ships with VS 2015. ▪ The philosophy behind this version is straightforward: improve simple everyday coding scenarios, without adding much conceptual baggage. ▪ The features should make code lighter without making the language heavier.
5. Auto-property enhancements ▪ Initializers for auto-properties public class Customer { public string First { get; set; } = "Jane"; public string Last { get; set; } = "Doe"; }
6. Auto-property enhancements ▪ Getter-only auto-properties public class Customer { public string First { get; } = "Jane"; public string Last { get; } = "Doe"; } public class Customer { public string Name { get; } public Customer(string first, string last) { Name = first + " " + last; } }
7. Expression-bodied function members ▪ Expression bodies on method-like members public Point Move(int dx, int dy) => new Point(x + dx, y + dy); public static Complex operator +(Complex a, Complex b) => a.Add(b); public static implicit operator string(Person p) => p.First + " " + p.Last; public void Print() => Console.WriteLine(First + " " + Last);
8. Expression-bodied function members ▪ Expression bodies on property-like function members public string Name => First + " " + Last; public Customer this[long id] => store.LookupCustomer(id);
9. Using static using static System.Console; using static System.Math; using static System.DayOfWeek; class Program { static void Main() { WriteLine(Sqrt(3*3 + 4*4)); WriteLine(Friday - Monday); } }
10. Extension methods using static System.Linq.Enumerable; // The type, not the namespace class Program { static void Main() { var range = Range(5, 17); // Ok: not extension var odd = Where(range, i => i % 2 == 1); // Error, not in scope var even = range.Where(i => i % 2 == 0); // Ok } }
11. Null-conditional operators int? length = customers?.Length; // null if customers is null Customer first = customers?[0]; // null if customers is null int length = customers?.Length ?? 0; // 0 if customers is null int? first = customers?[0].Orders.Count(); // new int? first = (customers != null) ? customers[0].Orders.Count() : null; // old int? first = customers?[0].Orders?.Count(); // Chained PropertyChanged?.Invoke(this, args); // Invoke on ?
12. String interpolation var s = String.Format("{0} is {1} year{{s}} old", p.Name, p.Age); var s = $"{p.Name} is {p.Age} year{{s}} old"; var s = $"{p.Name,20} is {p.Age:D3} year{{s}} old"; var s = $"{p.Name} is {p.Age} year{(p.Age == 1 ? "" : "s")} old";
13. nameof expressions if (x == null) throw new ArgumentNullException(nameof(x)); WriteLine(nameof(person.Address.ZipCode)); // prints "ZipCode"
14. Index initializers var numbers = new Dictionary<int, string> { [7] = "seven", [9] = "nine", [13] = "thirteen" };
15. Exception filters try { … } catch (MyException e) when (myfilter(e)) { … } private static bool Log(Exception e) { /* log it */ ; return false; } … try { … } catch (Exception e) when (Log(e)) {}
16. Await in catch and finally blocks Resource res = null; try { res = await Resource.OpenAsync(…); // You could do this. } catch(ResourceException e) { await Resource.LogAsync(res, e); // Now you can do this … } finally { if (res != null) await res.CloseAsync(); // … and this. }
17. MvvmCross & C#6 Building Native Cross-Platform Apps
18. Why Mvvm? View Binder ViewModel Model Button Text 1. Action 1. Action 3. Command 5. Notify change 6. Change data 4. Access data 2. Event handling
19. Why MvvmCross? ▪ Cross-platform awesomeness! ▪ Support for all major platforms ▪ Most advanced Mvvm library for Xamarin and .NET cross platform ▪ Large and engaged community ▪ Fast release cycle ▪ Clean and easy conventions Miguel de Icaza (Xamarin CTO) “I love MvvmCross” ▪ Used by many enterprise companies e.g: - Microsoft - Xamarin inc. - Dutch government - Olo - Nokia Scott Hanselman (Microsoft Developer Evangelist) “I am really impressed with MvvmCross”
20. MvvmCross supported platforms ▪ Android ▪ iOS ▪ Windows ▪ Xamarin.Forms ▪ tvOS ▪ Google wear ▪ iWatch ▪ Mac
21. MvvmCross details Highlights ▪ Flexible architecture ▪ PCL based ▪ Inversion of Control ▪ Dependency injection ▪ Value Converters ▪ Bindings ▪ Testable ▪ Plugins Resources ▪ Github.com/MvvmCross ▪ MvvmCross.com ▪ Slack (#mvvmcross) ▪ Stackoverflow ▪ Xamarin Forums
22. Presenters Specifications ▪ Customize view presentation ▪ Platform-specific ▪ Still retain View Model logic ▪ Presentation hints Examples ▪ Tabs / Panorama ▪ Split View / Master-Detail ▪ Fragments ▪ Modals ▪ Hamburger menu
23. Plugins ▪ Messenger ▪ Phone Call ▪ Picture Chooser ▪ SQLite ▪ Visibility ▪ Web Browser + Many More! MvvmCross ▪ Accelerometer ▪ Download Cache ▪ Email ▪ File ▪ Json ▪ Localization ▪ Location Plugins available at https://github.com/MvvmCross/MvvmCross-Plugins
24. Generics ▪ MvvmCross uses CoC (Convention over Configuration) by default - LoginView > LoginViewModel ▪ Generics can be used too - LoginView : MvxActivity<LoginViewModel> - MainView : MvxActivity<SomeDifferentNameViewModel> ▪ Possible to override in setup.cs - protected override IDictionary<Type, Type> GetViewModelViewLookup()
25. IoC (Inversion of Control) 1. Use interfaces 2. Define implementation of interfaces at runtime 3. Job done! :) ▪ Singleton: Mvx.RegisterSingleton<T>(); ▪ Lazy: Mvx.ConstructAndRegisterSingleton<T>(); ▪ Dynamic: Mvx.RegisterType<T>(); Mvx.Resolve<T>();
26. Tips ▪ Keep it simple ▪ Separation of Concerns ▪ Don’t try to invent the wheel again, use plugins, samples, etc ▪ Use Xamarin player or GenyMotion as emulator for Android ▪ Test all changes (UITest, Unit test, etc) ▪ Use a common PCL profile (profile7 or profile259) or .NET Platform Standard ▪ Enable “Analysis” XS > Preferences > Text Editor > Source Analysis > Enable ▪ Get help on Slack: https://xamarinchat.herokuapp.com/ ▪ Follow influencers on Twitter #Xamarin #MvvmCross ▪ Join the MvvmCross LinkedIn group