Question

i you please help me out with my problem i am trying to create a function that output the data on a dropdownlist an setting my parameters my code goes as follow :

        public static List<string> GetTracks(out List<string> trackIds, string conferenceId)
    {

        var res = new List<string>();
        trackIds = new List<string>();
        var sqlCon = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
        SqlCommand cmd = new SqlCommand("select Track_name,Track_ID from TrackCommittee where Conference_id= @conferenceId", sqlCon);
        DataSet ds = new DataSet();
        cmd.Connection.Open();
        cmd.Parameters.Add(new SqlParameter("@conferenceId", conferenceId));



        using (SqlDataReader sdr = cmd.ExecuteReader())
        {
       while (sdr.Read())
       {
        res.Add(sdr.GetString(sdr.GetOrdinal("Track_name")));
        trackIds.Add(sdr.GetInt32(sdr.GetOrdinal("Track_ID")).ToString());
       }
               }


        cmd.Connection.Close();
        cmd.Dispose();
        return res;
    }

thanking you in advance

Answer 1

Re-write the entire function like this:

public static IEnumerable<ListItem> GetTracks(string conferenceId)
{
    using (var sqlCon = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
    using (var cmd = new SqlCommand("select Track_name,Track_ID from TrackCommittee where Conference_id= @conferenceId", sqlCon))
    {

        cmd.Parameters.Add("@conferenceId", SqlDbType.Int).Value = conferenceId;
        sqlCon.Open();

        using (SqlDataReader sdr = cmd.ExecuteReader())
        {
            while (sdr.Read())
            {
                yield return new ListItem(sdr[0].ToString(), sdr[1].ToString());
            }
        }
    }
}

---

And update your calling code like this:

if (string.IsNullOrEmpty(os.SelectedValue)) 
{
    os.Items.AddRange(GetTracks("all").ToArray());
}

And for better separation of presention and data tiers, I would modify GetTracks to return KeyValuePairs and the calling to add a select projection from KeyValuePair to ListItem.