TemparatureConverter/TemparatureConverter.cs

public class TemparatureConverter
{
    public Dictionary<string, ITemperatureUnit> Dictionary { get; private set; } = null;

    public TemparatureConverter()
    {
        IEnumerable<Type> temparatureUnitTypes = AppDomain.CurrentDomain.GetAssemblies().SelectMany(assembly => assembly.GetTypes()).Where(type => type.GetInterfaces().Contains(typeof(ITemperatureUnit)));

        Dictionary = new Dictionary<string, ITemperatureUnit>(temparatureUnitTypes.Count());

        foreach (var temparatureUnitType in temparatureUnitTypes)
            Dictionary.Add(temparatureUnitType.Name, Activator.CreateInstance(temparatureUnitType) as ITemperatureUnit);
    }

    public float Convert(float value, ITemperatureUnit from, ITemperatureUnit to)
    {
        float celciusValue = from.ToCelcius(value);
        return to.FromCelcius(celciusValue);
    }

    // public List<float> ConvertToAll(float value, ITemperatureUnit from)
    // {
    //     List<float> list = new List<float>(Dictionary.Count);

    //     foreach (var toUnitPair in Dictionary)
    //         list.Add(Convert(value, from, toUnitPair.Value));

    //     return list;
    // }
}