using System;

using System.IO;

​

using KGySoft.CoreLibraries;

using KGySoft.ComponentModel;

​

using NUnit.Framework;

public class Example

{

    private class TestClass : ObservableObjectBase

    {

        public string TestProp { get => Get<string>(); set => Set(value); }

    }

​

    public static readonly ICommand LogPropChangeCommand = new SourceAwareTargetedCommand<PropertyChangedExtendedEventArgs, TextWriter>((src, state, writer) =>

    {

        writer.WriteLine($"{src.EventArgs.PropertyName}: {src.EventArgs.OldValue} -> {src.EventArgs.NewValue}");

        state.AsDynamic.TriggerCount = state.GetValueOrDefault<int>("TriggerCount") + 1;

    });

​

    public static void Main()

    {

        var test = new TestClass();

        ICommandBinding binding = LogPropChangeCommand.CreateBinding(test, "PropertyChanged", Console.Out);

​

        Assert.IsFalse(binding.State.ContainsKey("TriggerCount"));

        test.TestProp = "Alpha";

        Assert.AreEqual(2, binding.State.AsDynamic.TriggerCount); // IsModified, TestProp

​

        // not triggered again after disposing

        binding.Dispose();

        test.TestProp = "Beta";

        Assert.AreEqual(2, binding.State.AsDynamic.TriggerCount);

​

        // creating alternatively (command itself was not disposed)

        binding = LogPropChangeCommand.CreateBinding()

            .AddSource(test, "PropertyChanged")

            .AddTarget(Console.Out);

​

        Assert.IsFalse(binding.State.ContainsKey("TriggerCount"));

        test.TestProp = "Gamma";

        Assert.AreEqual(1, binding.State.AsDynamic.TriggerCount); // new state, only TestProp changed

​

        binding.InvokeCommand("Fake sender", "Fake event name", new PropertyChangedExtendedEventArgs("old", "new", "Fake property name"));

        Assert.AreEqual(2, binding.State.AsDynamic.TriggerCount); // our manual trigger

    }

}