Thank You for your support But I got the solution
This function i used without changing anything
crystalReportViewer1.SelectionFormula = "{BuyerDetailSeller.Ddate} >= CDATE('" + fromdate1.Value.ToString("yyyy,MM,dd") + "') AND {BuyerDetailSeller.Ddate} <= CDATE('" + todate1.Value.ToString("yyyy,MM,dd") + "')";