R3/sandbox/ConsoleApp1/Program.cs

using R3;
using System.ComponentModel.DataAnnotations;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Text.Json.Serialization.Metadata;

// CollectionsMarshal.GetValueRef
var v = new ClampedReactiveProperty2<int>(5, 10, 30);

Console.WriteLine(v.Value);


public sealed class ClampedReactiveProperty<T>(T initialValue, T min, T max)
    : ReactiveProperty<T>(initialValue) where T : IComparable<T>
{
    private static IComparer<T> Comparer { get; } = Comparer<T>.Default;

    protected override void OnValueChanging(ref T value)
    {
        if (Comparer.Compare(value, min) < 0)
        {
            value = min;
        }
        else if (Comparer.Compare(value, max) > 0)
        {
            value = max;
        }
    }
}


public sealed class ClampedReactiveProperty2<T>
    : ReactiveProperty<T> where T : IComparable<T>
{
    private static IComparer<T> Comparer { get; } = Comparer<T>.Default;

    readonly T min, max;

    // callOnValueChangeInBaseConstructor to avoid OnValueChanging call before min, max set.
    public ClampedReactiveProperty2(T initialValue, T min, T max)
        : base(initialValue, EqualityComparer<T>.Default, callOnValueChangeInBaseConstructor: false)
    {
        this.min = min;
        this.max = max;

        // modify currentValue manually
        OnValueChanging(ref GetValueRef());
    }

    protected override void OnValueChanging(ref T value)
    {
        if (Comparer.Compare(value, min) < 0)
        {
            value = min;
        }
        else if (Comparer.Compare(value, max) > 0)
        {
            value = max;
        }
    }
}





//[JsonConverter(typeof(IgnoreCaseStringReactivePropertyJsonConverter))]
public class IgnoreCaseStringReactiveProperty : ReactiveProperty<string>
{
    public IgnoreCaseStringReactiveProperty(string value)
        : base(value, StringComparer.OrdinalIgnoreCase)
    {

    }
}

internal class IgnoreCaseStringReactivePropertyJsonConverter : ReactivePropertyJsonConverter<string>
{
    protected override ReactiveProperty<string> CreateReactiveProperty(string value)
    {
        return new IgnoreCaseStringReactiveProperty(value);
    }
}