source: Common/FileExt.cs

using System.IO;
using System.Linq;

namespace Common
{
    public static class FileExt
    {
        public static void WriteAllBytesUpdate(string fileName, byte[] content)
        {
            if (File.Exists(fileName))
            {
                byte[] previousContent = File.ReadAllBytes(fileName);
                if (!previousContent.SequenceEqual(content)) File.WriteAllBytes(fileName, content);
            } else File.WriteAllBytes(fileName, content);
        }

        public static void WriteAllTextUpdate(string fileName, string content)
        {
            if (File.Exists(fileName))
            {
                string previousContent = File.ReadAllText(fileName);
                if (previousContent != content) File.WriteAllText(fileName, content);
            } else File.WriteAllText(fileName, content);
        }

        public static string GetExactPathName(string pathName)
        {
            if (!(File.Exists(pathName) || Directory.Exists(pathName)))
                return pathName;

            var di = new DirectoryInfo(pathName);

            if (di.Parent != null)
            {
                return Path.Combine(
                    GetExactPathName(di.Parent.FullName),
                    di.Parent.GetFileSystemInfos(di.Name)[0].Name);
            }
            else
            {
                return di.FullName.ToUpper();
            }
        }
    }
}