How to fetch record from database to dropdown in C#

SqlConnection conn = new SqlConnection();
conn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings[dbConnection].ConnectionString;

SqlCommand comd = new SqlCommand();
comd.CommandText = "select distinct FIELD from TABLE";
comd.Connection = conn;
conn.Open();
SqlDataAdapter dap = new SqlDataAdapter(comd);
dap.Fill(ds2);
try
{
    for (int a = 0; a < ds2.Tables[0].Rows.Count; a++)
    {
        ddldropdown.Items.Add(ds2.Tables[0].Rows[a][0].ToString().ToUpper());
    }
}
catch (Exception ex)
{
    MessageBox.Show("" + ex.Message);
}
finally
{
    conn.Close();
}