how can use crystal report for a particular person

i have a table of employee and i want generate crystal report for a particular employee by using ID of employee.

code of my crystal report:

protected void Page_Load(object sender, EventArgs e)
    {
        showreport();
    }
    private void showreport()
    {
        ReportDocument rd = new ReportDocument();
        if (Session["rptType"].ToString() == "Item")
        {
            rd.Load(Server.MapPath("~/CrystalReport.rpt"));
            CrystalReportViewer1.ReportSource = rd;
        }
    }