//合并Excel文件        private void MargeExcelFile(string destFile, string dirPath)        {            DirectoryInfo dir = new DirectoryInfo(dirPath);            FileInfo[] files = dir.GetFiles("*.xlsx");            Microsoft.Office.Interop.Excel.Application app = app = new Microsoft.Office.Interop.Excel.Application();            Microsoft.Office.Interop.Excel._Workbook m_Workbook = null;            try            {                Microsoft.Office.Interop.Excel._Workbook result = app.Workbooks.Add();                foreach (var item in files)                {                    m_Workbook = app.Workbooks.Open(Path.GetFullPath(item.FullName));                    foreach (Microsoft.Office.Interop.Excel._Worksheet each in m_Workbook.Sheets)                    {                        each.Copy(result.Worksheets[1]);                    }                }                if (File.Exists(destFile) == true)                {                    File.Delete(destFile);                }                result.SaveAs(destFile);            }            catch            {            }            finally            {                if (m_Workbook != null)                {                    m_Workbook.Close();                }                app.Quit();            }        }