retrieving data and update not working in my form

i'm new to asp 
i write the simple form which retirve the data in form but while try to update the it does not work. VS does not shows any error
code is as follows

using System.Configuration; using System.Data.SqlClient; using System.Data;
namespace MIS { public partial class followups : System.Web.UI.Page { string strcon = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString; protected void Page_Load(object sender, EventArgs e) { SqlConnection con = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand("select * from enquiry where EnquiryID='" + Request.QueryString["EnquiryID"] + "'", con); con.Open(); SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read()) { txtid.Text = Request.QueryString["EnquiryID"]; txtname.Text = dr[1].ToString();
} con.Close();
...