Report viewer is not rending in browser

<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="show" />
<CR:CrystalReportViewer ID="CrystalReportViewer1"  runat="server" AutoDataBind="true" />

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Configuration;
using MySql.Data.MySqlClient; 
using CrystalDecisions.CrystalReports.Engine;
using CrystalDecisions.Shared;

namespace CRM_And_Quotation_System
{
    public partial class WebForm2 : System.Web.UI.Page
    {
        string CS = ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString;
        protected void Page_Load(object sender, EventArgs e)
        {
            
        }

        protected void Button1_Click(object sender, EventArgs e)
        {

            CrystalReportViewer1.Visible = true;
            MySqlConnection con = new MySqlConnection(CS);
            con.Open();
            string query = "select * from partmaster";
            MySqlDataAdapter adr = new MySqlDataAdapter(query, con);
            DataSet2 ds = new DataSet2();
            adr.Fill(ds, "partmaster");
            ReportDocument doc = new ReportDocument();
            doc.Load(Server.MapPath("CrystalReport7.rpt"));
            doc.SetDataSource(ds);
            CrystalReportViewer1.ReportSource = doc;
            CrystalReportViewer1.DataBind();
            CrystalReportViewer1.RefreshReport();           
            }

      
        protected void CrystalReportViewer1_Init(object sender, EventArgs e)
        {

        }

        protected void CrystalReportViewer1_Init1(object sender, EventArgs e)
        {

        }
        }
    }