public static void SaveToFile(NPOI.SS.UserModel.IWorkbook workbook, string fileName) { System.IO.FileInfo fileInfo = new System.IO.FileInfo(fileName); System.IO.FileStream fileStream = new System.IO.FileStream(fileInfo.FullName, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite); workbook.Write(fileStream); fileStream.Close(); workbook.Close(); }