sql statement supposed to have 2 distinct rows, but only 1 is returned - sql

Question

I have an sql statement that is supposed to return 2 rows. the first with psychological_id = 1, and the second, psychological_id = 2. here is the sql statement
select * from psychological where patient_id = 12 and symptom = 'delire';
But with this code, with which I populate an array list with what is supposed to be 2 different rows, two rows exist, but with the same values: the second row.
OneSymptomClass oneSymp = new OneSymptomClass();
ArrayList oneSympAll = new ArrayList();
string connStrArrayList = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\PatientMonitoringDatabase.mdf; " +
"Initial Catalog=PatientMonitoringDatabase; " +
"Integrated Security=True";
string queryStrArrayList = "select * from psychological where patient_id = " + patientID.patient_id + " and symptom = '" + SymptomComboBoxes[tag].SelectedItem + "';";
using (var conn = new SqlConnection(connStrArrayList))
using (var cmd = new SqlCommand(queryStrArrayList, conn))
{
conn.Open();
using (SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
oneSymp.psychological_id = Convert.ToInt32(rdr["psychological_id"]);
oneSymp.patient_history_date_psy = (DateTime)rdr["patient_history_date_psy"];
oneSymp.strength = Convert.ToInt32(rdr["strength"]);
oneSymp.psy_start_date = (DateTime)rdr["psy_start_date"];
oneSymp.psy_end_date = (DateTime)rdr["psy_end_date"];
oneSympAll.Add(oneSymp);
}
}
conn.Close();
}
OneSymptomClass testSymp = oneSympAll[0] as OneSymptomClass;
MessageBox.Show(testSymp.psychological_id.ToString());
the message box outputs "2", while it's supposed to output "1". anyone got an idea what's going on?

Answer 1

You're adding the same instance to the ArrayList twice. Try this:
List<OneSymptomClass> oneSympAll = new List<OneSymptomClass>();
string connStrArrayList =
"Data Source=.\\SQLEXPRESS;" +
"AttachDbFilename=|DataDirectory|\\PatientMonitoringDatabase.mdf; " +
"Initial Catalog=PatientMonitoringDatabase; " +
"Integrated Security=True";
Patient patientID;
string queryStrArrayList =
"select * from psychological where patient_id = " +
patientID.patient_id + " and symptom = '" +
SymptomComboBoxes[tag].SelectedItem + "';";
using (var conn = new SqlConnection(connStrArrayList))
{
using (var cmd = new SqlCommand(queryStrArrayList, conn))
{
conn.Open();
using (SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
OneSymptomClass oneSymp = new OneSymptomClass();
oneSymp.psychological_id =
Convert.ToInt32(rdr["psychological_id"]);
oneSymp.patient_history_date_psy =
(DateTime) rdr["patient_history_date_psy"];
oneSymp.strength = Convert.ToInt32(rdr["strength"]);
oneSymp.psy_start_date =
(DateTime) rdr["psy_start_date"];
oneSymp.psy_end_date =
(DateTime) rdr["psy_end_date"];
oneSympAll.Add(oneSymp);
}
}
conn.Close();
}
}
MessageBox.Show(oneSympAll[0].psychological_id.ToString());
MessageBox.Show(oneSympAll[1].psychological_id.ToString());
Note that I replaced the ArrayList with a List<OneSymptomClass>. There is no reason to use ArrayList unless you're using .NET 1.1.

Answer 2

thx for the tip John Saunders. I added a line that makes it work. was that what you were gonna suggest me?
while (rdr.Read())
{
oneSymp = new OneSymptomClass();
oneSymp.psychological_id = Convert.ToInt32(rdr["psychological_id"]);
oneSymp.patient_history_date_psy = (DateTime)rdr["patient_history_date_psy"];
oneSymp.strength = Convert.ToInt32(rdr["strength"]);
oneSymp.psy_start_date = (DateTime)rdr["psy_start_date"];
oneSymp.psy_end_date = (DateTime)rdr["psy_end_date"];
oneSympAll.Add(oneSymp);
}