How to convert xlsx files into 2003 xls files programatically in C#?

Question

I\'ve found ExcelPackage, a better library than Excel Interop API to create and mantain programatically excel sheets, but they are generated in .xlsx. Most of people that wi

Answer 1

Here is a piece of code from my project with IBM iSeries. It will convert ANY Excel file to Excel 2003:

string MOVE_DOWNLOADED(string FILENAME)
{
  string Path = FILENAME;
  Microsoft.Office.Interop.Excel.ApplicationClass app = new Microsoft.Office.Interop.Excel.ApplicationClass();           
  Microsoft.Office.Interop.Excel.Workbook workBook = app.Workbooks.Open(Path,
    0,
    true,
    5,
    "",
    "",
    true,
    Microsoft.Office.Interop.Excel.XlPlatform.xlWindows,
    "\t",
    false,
    false,
    0,
    true,
    1,
    0);

  string retval = System.Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\" + "_tmp_" + ".xlsx";

  try
  {
    workBook.SaveAs(retval, 
      Microsoft.Office.Interop.Excel.XlFileFormat.xlExcel9795, 
      null, 
      null, 
      false, 
      false, 
      Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, 
      false, 
      false,
      null,
      null,
      null);
  }
  catch (Exception E)
  {
    MessageBox.Show(E.Message);
  }

  workBook.Close(null, null, null);
  System.Runtime.InteropServices.Marshal.ReleaseComObject(workBook);
  workBook = null;
  GC.Collect(); // force final cleanup!

  return retval;    
}