Just Use Below Code :
add three References first :
using CrystalDecisions.CrystalReports.Engine;
using CrystalDecisions.Shared;
using CrystalDecisions.Reporting;
protected void Page_Init(object sender, EventArgs e)
{
ReportDocument cr;
String data = "SELECT * from tablename";
SqlDataAdapter ad1 = new SqlDataAdapter(data, connection);
DataSet ds1 = new DataSet();
ad1.Fill(ds1);
path = Server.MapPath("report1.rpt");
cr = new ReportDocument();
cr.Load(path);
cr.SetDataSource(ds1.Tables[0]);
CrystalReportViewer1.ReportSource = cr;
}
this will help you if not please post it.
Enjoy.