ReportDocument.Refresh() error for Crystal Reports and ASP.Net

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ASP.NET

CrystalReports

I have a code for Crystal Reports and it is giving me an error.

ReportDocument.Refresh();

An object reference is required for the non-static field, method, or property 'CrystalDecisions.CrystalReports.Engine.ReportDocument.Refresh()'

Why am I getting this error?

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using CrystalDecisions.Web;
using CrystalDecisions.CrystalReports.Engine;
using CrystalDecisions.Shared;
using CrystalDecisions.Windows;
using CrystalDecisions.ReportSource;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Xml.Linq;
using System.Web.SessionState;


namespace SACSCOCLogin1._1
{
    public partial class ReportA : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            TextBoxINST_ID.Text = Session["inst_id"].ToString();
            CrystalReportViewer1.Visible = true;
            
            ReportDocument CrystalReport = new ReportDocument();
            CrystalReport.Load(Server.MapPath("~/Reports/ReportA.rpt"));
            CrystalReport.Refresh();
            CrystalReport.SetDatabaseLogon
            ("Admin", "master22", @"SQL", "Hot");
            CrystalReportViewer1.ReportSource = CrystalReport;
            CrystalReportViewer1.DataBind();
        }
    }
}