Preciso formatar uma celular tipo 50000,00 quero que fique 50.000,00 com fazer isso utilizando flexcel?

The best way to do this using APIMate, which is installed with FlexCel. (search for it in the start menu)

Just create an empty file with Excel, and format it as you want. Then save the file, and open it with APIMate.

I just did it here, and FlexCel reports this code:

 //Set the cell values
  fmt := xls.GetCellVisibleFormatDef(1, 1);
  fmt.Format := '#,##0.00';
  xls.SetCellFormat(1, 1, xls.AddFormat(fmt));
  xls.SetCellValue(1, 1, 50000);

Note that even if your decimal separator is ";" instead of ".", you always have to use "." as decimal separator when setting the format string in FlexCel.

Descobrir o apimate agora sim. Ja tinha feito. Obrigado.