i hope this help :-
DataSet ds = new DataSet();
creport_laundry crReportDocument = new creport_laundry();
ReportDocument rptFile = new ReportDocument();
ds = clsHlpr.ExecuteDataset(connection_name, CommandType.Text, "select * from abc");
if (ds.Tables[0].Rows.Count > 0)
{
rptform.Text = ".........";
rptFile.Load(Application.StartupPath + "\\mainR.rpt");
crReportDocument.crys.ReportSource = rptFile;
rptFile.SetDatabaseLogon("admin", "lbbs");
rptFile.SetDataSource(ds);
crReportDocument.crys.RefreshReport();
rptFile.Refresh();
rptFile.PrintToPrinter(1, false, 0, 0);
crReportDocument.crys.Show();
crReportDocument.Show();
}