KoKo 1.0.0

KoKo

KoKo lets you create Property objects as fields of your models.

Unlike built-in 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 manually writing any event handling code.

Installation

KoKo on NuGet Gallery

1. Right-click on your C# project and go to Manage NuGet Packages
2. Under Browse, search for KoKo
3. Click the down arrow button for KoKo

Usage

1. Create a class to act as your business or view model
2. Import the KoKo.Property namespace
3. Add some Property fields
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 Project1
{
    class Person
    {
        readonly StoredProperty<string> firstName;
        readonly StoredProperty<string> lastName;
        readonly Property<string> fullName;

        Person(string firstName, string lastName)
        {
            this.firstName = new StoredProperty<string>(firstName);
            this.lastName = new StoredProperty<string>(lastName);

            fullName = new DerivedProperty<string>(new[] { this.firstName, this.lastName },
                () => $"{this.firstName.Value} {this.lastName.Value}");
        }

        void ChangeFirstName(string newFirstName)
        {
            firstName.Value = newFirstName;
        }
    }
}

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 full name will be automatically updated.

person.ChangeFirstName("Bob");
Console.WriteLine(person.fullName.Value); // Bob Smith

You can also use Properties with databinding:

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

Properties

StoredProperty

• Stores a single value in memory
• Value can be get or set imperatively
• Similar to a C# property, except you don't have to implement INotifyPropertyChanged yourself

var a = new StoredProperty<string>("world");
Console.WriteLine($"Hello {a.Value}"); // Hello world
a.Value = "world!";
Console.WriteLine($"Hello {a.Value}"); // Hello world!

DerivedProperty

• Automatically calculates its value from other dependency properties
• Cannot set the value directly, but you can get the value just like a StoredProperty

var b = new StoredProperty<int>(8);
var absoluteValueB = new DerivedProperty<int>(new[] { b }, () => System.Math.Abs(b.Value));
Console.WriteLine($"The absolute value of {b.Value} is {absoluteValueB.Value}."); // The absolute value of 8 is 8.
b.Value = -9;
Console.WriteLine($"The absolute value of {b.Value} is {absoluteValueB.Value}."); // The absolute value of -9 is 9.

PassthroughProperty

• Like a DerivedProperty, except it depends on a single property and does not transform the value at all

var a = new StoredProperty<double>(3.0);
var b = new PassthroughProperty<double>(a);
Console.WriteLine($"{b.Value} liters"); // 3 liters
a.Value = 5.0;
Console.WriteLine($"{b.Value} liters"); // 5 liters