In my .net core console application, I am reading multiple excel files and bulk copy data into a database table. It is working as it is expected, I wonder if there are any improvements to make it better. So I would be glad if you can share your comments.

Thanks in advance.

class Program
    {
        static async Task Main(string[] args)
        {
            try
            {
                string s = null;
                var d = new DirectoryInfo(@"C:\Test");
                var files = d.GetFiles("*.xlsx");
                var usersList = new List<User>();

                foreach (var file in files)
                {
                    var fileName = file.FullName;

                    using var package = new ExcelPackage(file);
                    ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
                    var currentSheet = package.Workbook.Worksheets;
                    var workSheet = currentSheet.First();
                    var noOfCol = workSheet.Dimension.End.Column;
                    var noOfRow = workSheet.Dimension.End.Row;
                    for (int rowIterator = 2; rowIterator <= noOfRow; rowIterator++)
                    {
                        var user = new User
                        {
                            GameCode = workSheet.Cells[rowIterator, 1].Value?.ToString(),
                            Count = Convert.ToInt32(workSheet.Cells[rowIterator, 2].Value),
                            Email = workSheet.Cells[rowIterator, 3].Value?.ToString(),
                            Status = Convert.ToInt32(workSheet.Cells[rowIterator, 4].Value)
                        };


                        usersList.Add(user);
                    }
                }

                var conn = ConfigurationManager.ConnectionStrings["Development"].ConnectionString;
                await using var connString = new SqlConnection(conn);
                connString.Open();
                await BulkWriter.InsertAsync(usersList, "[Orders]", connString, CancellationToken.None);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
            
        }

        private class BulkWriter
        {
            private static readonly ConcurrentDictionary<Type, SqlBulkCopyColumnMapping[]> ColumnMapping =
                new ConcurrentDictionary<Type, SqlBulkCopyColumnMapping[]>();

            public static async Task InsertAsync<T>(IEnumerable<T> items, string tableName, SqlConnection connection,
                CancellationToken cancellationToken)
            {
                using var bulk = new SqlBulkCopy(connection);
                await using var reader = ObjectReader.Create(items);
                bulk.DestinationTableName = tableName;
                foreach (var colMap in GetColumnMappings<T>())
                    bulk.ColumnMappings.Add(colMap);
                await bulk.WriteToServerAsync(reader, cancellationToken);
            }

            private static IEnumerable<SqlBulkCopyColumnMapping> GetColumnMappings<T>() =>
                ColumnMapping.GetOrAdd(typeof(T),
                    type =>
                        type.GetProperties()
                            .Select(p => new SqlBulkCopyColumnMapping(p.Name, p.Name)).ToArray());
        }
    }

Updated version:

I also added excel extension change and moving excel into another folder. Any comments?

public static class Program
    {
        private static async Task ReadAllExcelFilesInDirectory(string path, List<User> usersList)
        {
            var dirInfo = new DirectoryInfo(path);
            var files = dirInfo.GetFiles("*.xlsx");
            foreach (var file in files)
                await ReadExcelFile(file, usersList);
        }

        private static async Task ReadExcelFile(FileInfo fileName, List<User> usersList)
        {
            const string destinationFile = @"T:\Test";

            if (fileName == null) throw new ArgumentNullException(nameof(fileName));
            if (usersList == null) throw new ArgumentNullException(nameof(usersList));

            using var package = new ExcelPackage(fileName);
            ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
            var currentSheet = package.Workbook.Worksheets;
            var workSheet = currentSheet.First();
            var noOfCol = workSheet.Dimension.End.Column;
            var noOfRow = workSheet.Dimension.End.Row;
            for (var rowIterator = 2; rowIterator <= noOfRow; rowIterator++)
            {
                var user = new User
                {
                    GameCode = workSheet.Cells[rowIterator, 1].Value?.ToString(),
                    Count = Convert.ToInt32(workSheet.Cells[rowIterator, 2].Value),
                    Email = workSheet.Cells[rowIterator, 3].Value?.ToString(),
                    Status = Convert.ToInt32(workSheet.Cells[rowIterator, 4].Value)
                };


                usersList.Add(user);
            }

            //Change extension
            await using var newfile = File.OpenWrite(fileName.FullName + ".old");
            await package.SaveAsAsync(newfile);
            // To move a file or folder to a new location
            File.Move(fileName.FullName, destinationFile + "\\" + fileName.Name);
        }

        private static async Task InsertUsersIntoDatabase(List<User> usersList)
        {
            var conn = ConfigurationManager.ConnectionStrings["Development"].ConnectionString;
            await using var connString = new SqlConnection(conn);
            connString.Open();
            await InsertAsync(usersList, "[GameAPI].[dbo].[A101Orders]", connString, CancellationToken.None);
        }

        
        private static async Task Main(string[] args)
        {
            try
            {
                var usersList = new List<User>();
                await ReadAllExcelFilesInDirectory(
                    @"C:\Test", usersList);
                await InsertUsersIntoDatabase(usersList);

               
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }

        private static async Task InsertAsync<T>(IEnumerable<T> items, string tableName, SqlConnection connection,
            CancellationToken cancellationToken)
        {
            using var bulk = new SqlBulkCopy(connection);
            await using var reader = ObjectReader.Create(items);
            bulk.DestinationTableName = tableName;
            var properties = typeof(T).GetProperties();
            foreach (var prop in properties)
                bulk.ColumnMappings.Add(new SqlBulkCopyColumnMapping(prop.Name, prop.Name));
            await bulk.WriteToServerAsync(reader, cancellationToken);
        }

        
    }