hey i am tryin to get values from my database into drop down list....but theres some prob wid ma code...can anyone help me out plz

[C# Programming]

protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
string connection1 = ConfigurationManager.AppSettings["conn"];
OleDbConnection con1 = new OleDbConnection(connection1);
con1.Open();



OleDbDataReader dr;

string query = "select DISTINCT DEPARTMENT from TIME_DETAILS ";
//OleDbDataAdapter da1 = new OleDbDataAdapter(query,con1);
//DataSet ds1 = new DataSet();
//da1.Fill(ds1);
OleDbCommand cmd = new OleDbCommand(query,con1);

dr = cmd.ExecuteReader();

while (dr.Read())
{
DropDownList2.Items.Add(dr[0].ToString());
DropDownList2.DataValueField.Insert(dr[0]);
}



}