System.Data.OleDb.OleDbDataReader does not contain a definition for Item and no extension method Item

How to solve the problem ?

Error 1 'System.Data.OleDb.OleDbDataReader' does not contain a definition for 'Item' and no extension method 'Item' accepting a first argument of type 'System.Data.OleDb.OleDbDataReader' could be found (are you missing a using directive or an assembly reference?) 

public partial class Default2 : System.Web.UI.Page
{    
	System.Data.OleDb.OleDbConnection Con = new System.Data.OleDb.OleDbConnection(System.Web.Configuration.WebConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString);

        protected void Page_Load(object sender, EventArgs e)
    {
        OleDbCommand cmd2 = new OleDbCommand("select Q,a1,a2,a3,a4 from ope", Con);
        Con.Open();
        OleDbDataReader dr = cmd2.ExecuteReader();
        if (dr.Read())
        {
            Label2.Text = dr[0].ToString();
            RadioButton1.Text = dr[1].ToString();
            RadioButton2.Text = dr[2].ToString();
            RadioButton3.Text = dr[3].ToString();
            RadioButton4.Text = dr[4].ToString();
        }
       
        Con.Close();
    }
        protected void Button4_Click(object sender, EventArgs e)
        {
            if (RadioButton1.Checked == false && RadioButton2.Checked == false && RadioButton3.Checked == false && RadioButton4.Checked == false)
            {
                return;
            }
            //Try
            //    If Request.Cookies("vv").Value = "t" Then
            //        Label3.Visible = True
            //        Exit Sub
            //    End If
            //Catch ex As Exception

            //End Try        
            byte x = 0;
            byte[] y = new byte[4];
            if (RadioButton1.Checked) { x = 0; goto x; }
            if (RadioButton2.Checked) { x = 1; goto x; }
            if (RadioButton3.Checked) { x = 2; goto x; }
            if (RadioButton4.Checked)
                x = 3;
        x:
            OleDbCommand cmd = new OleDbCommand("select r1,r2,r3,r4 from ope", Con);
            Con.Open();
            OleDbDataReader dr = cmd.ExecuteReader();
            if (dr.Read())
            {
                y[0] = dr.Item[0];
                y[1] = dr.Item[1];
                y[2] = dr.Item[2];
                y[3] = dr.Item[3];
            }
            dr.Close();
            Con.Close();
            y[x] += 1;
            OleDbCommand cmd2 = new OleDbCommand("update ope set r" + Convert.ToString(x + 1) + " = " + Convert.ToString(y[x]), Con);
            int updated = 0;
            Con.Open();
            updated = cmd2.ExecuteNonQuery();
            Con.Close();
            Panel1.Visible = false;
            Panelxxx.Visible = true;
        //     '==================================================
        //'==================================================
            int tx = y[0] + y[1] + y[2] + y[3];
            rr1.Text = RadioButton1.Text;
            rr2.Text = RadioButton2.Text;
            rr3.Text = RadioButton3.Text;
            rr4.Text = RadioButton4.Text;
            v1.Text = Convert.ToString(y[0]) + "صوت";
            h1.Text = Convert.ToString(Convert.ToInt32((y[0] / tx) * 100));
            Image1.Width = Convert.ToInt32(h1.Text * 2);
            v2.Text = Convert.ToString(y[1]) + "صوت";
            h2.Text = Convert.ToString(Convert.ToInt32((y[1] / tx) * 100));
            Image2.Width = Convert.ToInt32(h2.Text * 2);
            v3.Text = Convert.ToString(y[2]) + "صوت";
            h3.Text = Convert.ToString(Convert.ToInt32((y[2] / tx) * 100));
            Image3.Width = Convert.ToInt32(h3.Text * 2);
            v4.Text = Convert.ToString(y[3]) + "صوت";
            h4.Text = Convert.ToString(Convert.ToInt32((y[3] / tx) * 100));
            Image4.Width = Convert.ToInt32(h4.Text * 2);
            HttpCookie ck1 = new HttpCookie("vv", "t");
            Response.Cookies.Add(ck1);
            ck1.Expires = DateAndTime.Now.AddDays(20);
        }
}