private void export_Click(object sender, EventArgs e)
{
SaveFileDialog s_dialog = new SaveFileDialog();
s_dialog.DefaultExt = ".xls";
s_dialog.Filter = "Excel files (*.xls)|*.xls|All files (*.*)|*.*";
s_dialog.ShowDialog();
//slow method
//this.WriteToExcelSpreadsheet(s_dialog.FileName,ds.Tables[0]);
//my own class and methods for faster export
ExportToExcel export = new ExportToExcel(s_dialog.FileName,ds);
export.writeToExcel();
// EXPORT TO MS EXCEL METHOD
}