how to get checked chekbox while update from gridview
<p>in my project i use chekbox list...but while m get update from gridview i can't get chek chekbox...can any one help me</p>

<pre><code> SqlConnection Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ims"].ConnectionString);
 Conn.Open();
 DataSet ds1 = new DataSet();
 string querry = "Select po_tax from purchase_order where po_id='" + Request.QueryString["po_id"] + "'";

 // ds1 = obj1.SelectQuery(querry);
 SqlCommand cmd = new SqlCommand(querry,Conn);
 cmd.ExecuteNonQuery();

 SqlDataReader rdr;

 rdr = cmd.ExecuteReader();
 if (rdr.Read() == false)
 {
      //No Records
      rdr.Close();
      Conn.Close();
      Label3.Text = "No record found";
      return;
 }
 else
 {
      CheckBoxList chkbx = (CheckBoxList)form1.FindControl("CheckBoxList1");
      rdr.NextResult();
      if (rdr.IsClosed == false)
      {
           while (rdr.Read() == true) [problem ocures here. it does not executes i.e does not go inside curly braces. why?]
           {
                ListItem currentCheckBox = chkbx.Items.FindByValue(rdr["po_id"].ToString());
                if (currentCheckBox != null)
                {
                     currentCheckBox.Selected = true;
                }
           }
      }
      rdr.Close();
      //string[] items = returned_value_from_db.Split(',');
      string[] items = sb.ToString().Split(',');
      for (int i = 0; i &lt;= items.GetUpperBound(0); i++)
      {
           ListItem currentCheckBox = chkbx.Items.FindByValue(items[i].ToString());
           if (currentCheckBox != null)
           {
                currentCheckBox.Selected = true;
           }
      }
 }

 Conn.Close();
</code></pre>
