Masuit.Tools/Masuit.Tools.Core/Validator/MaxValueAttribute.cs

using System;
using System.ComponentModel.DataAnnotations;

namespace Masuit.Tools.Core.Validator
{
    public class MaxValueAttribute : ValidationAttribute
    {
        private double MaxValue { get; }
        public MaxValueAttribute(double value)
        {
            MaxValue = value;
        }
        public override bool IsValid(object value)
        {
            if (value is null)
            {
                return true;
            }
            var input = Convert.ToDouble(value);
            return input <= MaxValue;
        }

        /// <summary>Applies formatting to an error message, based on the data field where the error occurred.</summary>
        /// <param name="name">The name to include in the formatted message.</param>
        /// <returns>An instance of the formatted error message.</returns>
        public override string FormatErrorMessage(string name)
        {
            return base.FormatErrorMessage(name);
        }
    }
}