XGKYTJ/Solution/SiteLibrary/ObjectExtensions.cs

using NPOI.SS.UserModel;
using System;
using System.IO;
using System.Linq;
using System.Security.Cryptography;

namespace SiteLibrary
{
    public static class ObjectExtensions
    {
        public static string[] SplitBySpace(this string input)
        {
            return input.Split(' ').Where(o => o != null).Select(o => o.Trim()).Where(o => !string.IsNullOrEmpty(o)).ToArray();
        }

        public static string ToText(this ICell cell)
        {
            return (cell?.ToString() ?? "").Trim();
        }

        public static int? ToInt(this ICell cell)
        {
            if(int.TryParse(cell.ToText(), out int result))
            {
                return result;
            }
            return null;
        }

        public static string Md5(this string file)
        {
            using var md5 = MD5.Create();
            using var stream = File.OpenRead(file);
            var hash = md5.ComputeHash(stream);
            stream.Dispose();
            return BitConverter.ToString(hash).Replace("-", "").ToLower();
        }

        public static string ExtToLower(this string file)
        {
            if (!string.IsNullOrEmpty(file))
            {
                var ext = Path.GetExtension(file);
                var extLower = ext.ToLower();
                if (ext != extLower)
                {
                    return Path.Combine(Path.GetDirectoryName(file), Path.GetFileNameWithoutExtension(file) + extLower).Replace("\\", "/");
                }
            }
            return file;
        }
    }
}