FahrenheitConverter.cs

using System;
using System.Globalization;

namespace MauiWeatherForecast
{
    public class FahrenheitConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value == null)
            {
                return "0"; // or however you wish to handle null values
            }

            if (value is double fahrenheit)
            {
                double celsius = (fahrenheit - 32) * 5 / 9;
                return Math.Round(celsius).ToString();
            }
            else
            {
                throw new ArgumentException("Expected a double value.", nameof(value));
            }
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}