Data Bind Everything

@slodge Data-Bind Everything…

@slodge fun we’ve had extending data-binding in MvvmCross

@slodge MvvmCross

@slodge MvvmCross • C# • Microsoft, Xamarin and beyond! •
PCL • IoC • Convention-Based Mvvm • Data-Binding

@slodge • Building a Data-Binding Engine • MvvmCross v1/v2 Data-Binding
• MvvmCross v3 - Rio and Tibet • The Dark Side?

@slodge Data-Binding in Xaml/C#

@slodge Data-Binding in Xaml/C# ViewModel INotifyPropertyChanged Control TextProperty DependencyProperty DependencyObject
Values BindingOperations FirstName C# Property PropertyChanged C# Event

@slodge … in Android and iOS UIKit? ViewModel INotifyPropertyChanged Control
TextProperty DependencyProperty DependencyObject Values BindingOperations FirstName C# Property PropertyChanged C# Event

TextProperty DependencyProperty DependencyObject Values BindingOperations FirstName C# Property PropertyChanged C# Event Text TextChanged OurBindingEngine

@slodge What’s a Binding Engine do 1. Initially copy values
ViewModel -> View 2. When ViewModel changes, update View 3. When View changes, update ViewModel 4. Don’t loop! 5. When the View disappears, dispose the bindings

@slodge Creating a Binding Engine…

TextProperty DependencyProperty DependencyObject Values BindingOperations FirstName C# Property PropertyChanged C# Event Text TextChanged MvxBindingEngine

@slodge Syntax – Xaml/C# Text=“ {Binding Customer.Gender, Converter={StaticResource FormalGreeting}, FallbackValue=‘Mr’}”

@slodge Syntax - Json { “Text”: { “Path”:”Customer.Gender”, “Converter”:”FormalGreeting”, “FallbackValue”:”Mr”
} }

@slodge Syntax – “Swiss” Text Customer.Gender, Converter=FormalGreeting, FallbackValue=’Mr’

@slodge Syntax - Fluent set.Bind(label) .For(t => t.Text) .To(vm =>
vm.Customer.Gender) .WithConversion(“FormalGreeting”) .WithFallback(“Mr”)

@slodge Binding Parts • Path • Mode • Converter •
ConverterParameter • FallbackValue

@slodge Path • Simple FirstName • Chained Customer.FirstName • Indexed
Customers[0].FirstName Customers[“Fred”].FirstName • Whole Object .

@slodge Mode • One Way • Two Way • One
Way To Source • One Time • … and Default

@slodge Converters

@slodge Converters • Basic Conversion • FallbackValue • UnsetValue •
DoNothing

@slodge Core Demos

@slodge Binding Targets • It just works TM • When
it doesn’t just work: – Inheritance – Intermediate – Custom Bindings

@slodge Inheritance Android.Views.View MyShapeView TheShape TheShapeChanged

@slodge Intermediate Map MapMarkerHelper ItemsSource

@slodge Custom binding Button “Favorite” CustomBinding OurBindingEngine

@slodge Composite Binding Sources • Collections • Commands • I18n
• Dialogs

@slodge Collections

@slodge Commands

@slodge Internationalisation

@slodge Dialogs View ViewModel Command fired Show confirmation “MessageBox” Yes/No
result

@slodge Dialogs

@slodge Composite Demos

@slodge JavaScript envy • ko.observable • ko.computedValue • functions

@slodge Tibet Binding extensions • MultiBinding • Literals • +
- concatenation • Function-like ValueConversion • Recursive evaluation • ValueCombiners (MultiValueConverters) • If, Format, &&, ||, <, >, ==, …

@slodge Syntax – “Tibet”

@slodge Rio Extensions • Fody integration • Field Binding •
Method Bindings • Extensible – interfaces and plugins

@slodge Fody

@slodge Field Binding

@slodge Method Binding

@slodge All available in Xaml too

@slodge Tibet & Rio

@slodge Benefits • Code sharing • Designer-friendly • Testability •
Coder friendly

@slodge Some gaps/differences? • RelativeSource • ElementName • Validation and
Trigger • Multi-Binding • ICommand

@slodge “Overkill” • For small throwaway apps…

@slodge The Call Stack

@slodge Performance everyone (at least, more or less experienced developer)
knows that reflection is performance's "evil".

@slodge "We should forget about small efficiencies, say about 97%
of the time: premature optimization is the root of all evil" Performance

@slodge Performance Analysis Simple UI test: – ViewModel: 10000 *
“Value = Value+1” – View: TextView bound “Text Value”

@slodge Performance Results Baseline 2116 OneWay 2378 INotifyChanged 2066 TwoWayBaseline
6216 TwoWay 7092

@slodge Awesomeness

@slodge

@slodge Thanks for listening! https://github.com/mvvmcross https://github.com/reactiveUI https://github.com/MacawNL https://github.com/Fody @slodge @mvvmcross

Data Bind Everything

Data Bind Everything

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