KoKo 2.2.0

Full documentation on GitHub

Knockout for Cocoa, for C#

KoKo lets you create Property objects as members of your model classes.

Unlike native C# properties, KoKo Property objects automatically fire change events. They can be composed from multiple other Properties without the dependencies being aware of the dependents, and without writing any boilerplate event handling code. They are compatible with native C# properties and events, as well as with WPF and Windows Forms databinding.

These properties are very similar to what you would find in Knockout, MobX, and WPF's DependencyProperty. They do not rely on a presentation layer like WPF, and they do not require you to import and understand a large, overblown, confusing library like .NET Reactive Extensions/Rx.NET.

This library was ported from a Swift library by @abrindam called KoKo ("Knockout for Cocoa"), which was later open-sourced under the name Yoyo.

Requirements

• Any of the following runtimes
  • .NET Core 2.0 or later, including .NET 5 or later
  • .NET Framework 4.6.2 or later
  • Any other runtime that supports .NET Standard 2.0 or later

Usage

1. Create a class to act as your business or view model.
2. Import the KoKo.Property namespace.
3. Add some Property fields, one for each piece of data you want to represent.
4. Get and set their Value.

Example

This is a just a silly, simple example. Don't actually represent people's names this way.

using KoKo.Property;

namespace MyProject {

    public class Person {

        private StoredProperty<string> FirstName { get; }
        private StoredProperty<string> LastName { get; }
        public Property<string> FullName { get; }

        public Person(string firstName, string lastName) {
            FirstName = new StoredProperty<string>(firstName);
            LastName = new StoredProperty<string>(lastName);
            FullName = DerivedProperty<string>.Create(FirstName, LastName, (first, last) => $"{first} {last}");
        }

        public void SetFirstName(string firstName) {
            FirstName.Value = firstName;
        }

    }
}

Programmatic access

Now you can get a person object's autogenerated full name,

var person = new Person("Alice", "Smith");
Console.WriteLine(person.FullName.Value); // Alice Smith

and if you change a dependency value, the dependent full name will be automatically updated.

person.SetFirstName("Bob");
Console.WriteLine(person.FullName.Value); // Bob Smith

Data-bound access

You can also use Properties with databinding in WPF and Windows Forms:

<Label Content="{Binding FullName.Value}" />

private void Form1_Load(object sender, System.EventArgs e) {
    personNameLabel.DataBindings.Add("Text", model.FullName, "Value");
}

Remember to use the Value property in your databinding declarations, otherwise you won't get the property's value.

Full documentation on GitHub