R3Utility

A utility library for Cysharp/R3 that provides enhanced reactive programming capabilities, focusing on validation, property binding, and UI event observation.

🚨 Breaking Changes (v0.3.0)

Starting from version 0.3.0, ObservableCollectionsExtensions has been moved to a separate package: R3Utility.ObservableCollections. If you were using ObserveElementProperty, please install the new package and update your imports accordingly.

dotnet add package R3Utility.ObservableCollections

using R3Utility.ObservableCollections;

Features

Two-Way Binding Extensions

• Convert INotifyPropertyChanged properties to BindableReactiveProperty
• Automatic value propagation in both directions
• Support for deep property path binding (up to 3 levels)

Reactive Validation

• Combine multiple boolean observables with various logical operations
• Support for creating executable command sources based on validation states

Observable Element Property Monitoring (R3Utility.ObservableCollections)

• Observe changes in specific properties of elements within a collection.
• Customizable option, pushCurrentValueOnSubscribe to control initial value emission.
• Support for deep property path binding (up to 3 levels)

WinForms UI Event Observables (R3Utility.WinForms)

• Convert common UI events into observables
• Supports TextBox, Button, CheckBox, ComboBox, and Control drag-and-drop events

API Reference

ReactivePropertyExtensions

Method	Parameters	Return Type	Description
ToTwoWayBindableReactiveProperty<T, TProperty>	T value, Expression<Func<T, TProperty>> propertySelector	BindableReactiveProperty<TProperty>	Converts a single property to two-way bindable reactive property
ToTwoWayBindableReactiveProperty<T, TProperty1, TProperty2>	T value, Func<T, TProperty1?> propertySelector1, Func<TProperty1, TProperty2> propertySelector2	BindableReactiveProperty<TProperty2>	Converts a nested property (2 levels) to two-way bindable reactive property
ToTwoWayBindableReactiveProperty<T, TProperty1, TProperty2, TProperty3>	T value, Func<T, TProperty1?> propertySelector1, Func<TProperty1, TProperty2?> propertySelector2, Func<TProperty2, TProperty3> propertySelector3	BindableReactiveProperty<TProperty3>	Converts a deeply nested property (3 levels) to two-way bindable reactive property

ReactiveValidationHelper

Method	Parameters	Return Type	Description
CombineLatestValuesAreAllFalse	IEnumerable<Observable<bool>>	Observable<bool>	Combines multiple observables and returns true only when all source values are false
CombineLatestValuesAreAllTrue	IEnumerable<Observable<bool>>	Observable<bool>	Combines multiple observables and returns true only when all source values are true
CombineLatestValuesAreAnyFalse	IEnumerable<Observable<bool>>	Observable<bool>	Combines multiple observables and returns true when any source value is false
CombineLatestValuesAreAnyTrue	IEnumerable<Observable<bool>>	Observable<bool>	Combines multiple observables and returns true when any source value is true
CreateCanExecuteSource	IBindableReactiveProperty[]	Observable<bool>	Creates an observable that monitors HasErrors property of multiple BindableReactiveProperty instances

ObservableCollectionsExtensions(R3Utility.ObservableCollections)

Method	Parameters	Return Type	Description
ObserveElementProperty<T, TProperty>	IObservableCollection<T> source, Func<T, TProperty> propertySelector, bool pushCurrentValueOnSubscribe = true, CancellationToken cancellationToken = default	Observable<PropertyPack<T, TProperty>>	Observes a specific property of each element in a collection and emits its values.
ObserveElementProperty<T, TProperty1, TProperty2>	IObservableCollection<T> source, Func<T, TProperty1?> propertySelector1, Func<TProperty1, TProperty2> propertySelector2, bool pushCurrentValueOnSubscribe = true, CancellationToken cancellationToken = default	Observable<PropertyPack<T, TProperty2>>	Observes a nested property (2 levels) in a collection and emits its values.
ObserveElementProperty<T, TProperty1, TProperty2, TProperty3>	IObservableCollection<T> source, Func<T, TProperty1?> propertySelector1, Func<TProperty1, TProperty2> propertySelector2, Func<TProperty2, TProperty3> propertySelector3, bool pushCurrentValueOnSubscribe = true, CancellationToken cancellationToken = default	Observable<PropertyPack<T, TProperty3>>	Observes a deeply nested property (3 levels) in a collection and emits its values.

WinForms UIComponentExtensions (R3Utility.WinForms)

Method	Parameters	Return Type	Description
TextChangedAsObservable	TextBoxBase textBox	Observable<EventArgs>	Observes TextChanged event of a TextBoxBase.
ClickAsObservable	Button button	Observable<EventArgs>	Observes Click event of a Button.
CheckedChangedAsObservable	CheckBox checkBox	Observable<EventArgs>	Observes CheckedChanged event of a CheckBox.
SelectedIndexChangedAsObservable	ComboBox comboBox	Observable<EventArgs>	Observes SelectedIndexChanged event of a ComboBox.
SelectionChangeCommittedAsObservable	ComboBox comboBox	Observable<EventArgs>	Observes SelectionChangeCommitted event of a ComboBox.
DragEnterAsObservable	Control control	Observable<DragEventArgs>	Observes DragEnter event of a Control.
DragOverAsObservable	Control control	Observable<DragEventArgs>	Observes DragOver event of a Control.
DragLeaveAsObservable	Control control	Observable<EventArgs>	Observes DragLeave event of a Control.
DragDropAsObservable	Control control	Observable<DragEventArgs>	Observes DragDrop event of a Control.

Usage Examples

Two-Way Binding

// Create a BindableReactiveProperty<T> that is two-way bound
BindableReactiveProperty<string> name = item.ToTwoWayBindableReactiveProperty(x => x.Name);

// This will also update the Name property of the item object
name.Value = "X"; //item.Name = "X"

// This will also update the Value property of the BindableReactiveProperty
item.Name = "Y"; //name.Value = "Y"


// Deep property path binding
BindableReactiveProperty<string> nestedProperty = viewModel.ToTwoWayBindableReactiveProperty(
    x => x.User,
    x => x.Profile,
    x => x.DisplayName
);

Validation Helpers

// Combine multiple validation states
Observable<bool> isValid = ReactiveValidationHelper.CombineLatestValuesAreAllTrue(
      emailValidation,
      passwordValidation,
      termsAccepted
);

// Create executable command source
Observable<bool> canExecute = ReactiveValidationHelper.CreateCanExecuteSource(
      emailProperty,
      passwordProperty
);
command = canExecute.ToReactiveCommand();

Observing Properties in a Collection

using ObservableCollections;
using R3;
using R3Utility.ObservableCollections;

ObservableList<Item> collection = [];
Item item1 = new() { Name = "foo" };

collection.Add(item1);
var disposable = collection.ObserveElementProperty(x => x.Name, pushCurrentValueOnSubscribe: false)
                           .Subscribe(property => Console.WriteLine($"Instance:{property.Instance}, propertyName:{property.PropertyName}, Value:{property.Value}"));
        
//Changes are output. `Instance:WpfApp1.Item, propertyName:Name, Value:bar`
item1.Name = "bar";

disposable.Dispose();

Installation

dotnet add package R3Utility
dotnet add package R3Utility.ObservableCollections
dotnet add package R3Utility.WinForms

License

R3Utility is distributed under a free and open-source license. Feel free to use it in your projects!

Contributions

We welcome contributions to the R3Utility project! If you have any suggestions, bug reports, or feature requests, please feel free to open an issue or submit a pull request. We're excited to make R3Utility better together.