Crystal Report Printing in ASP.Net

function ShowCreprt()
{
string str_sql=null;
DataSet DsMain = new DataSet();
CrystalDecisions.CrystalReports.Engine.ReportDocument rp;

string reportPath = Server.MapPath("LogReport.rpt"); //Set path of Crystal Report

rp = new CrystalDecisions.CrystalReports.Engine.ReportDocument(); // Object of Report Document

sql = "Select l_name as username,'' as sno, userdetail.user_ip as uip from userdetail Where userdetail.user_id=" + int_loginID + " order by servertime";

//in DsMain i fill records as per above query

rp.FileName = reportPath;
rp.SetDataSource(dsmain.Tables[0]);

crviewer.ReportSource = rp;
//I have crviewer control on my page


}