Как считать строку из ObservableCollection по заданным параметрам?

public ObservableCollection<CreditsList> CreditsList()
        {
            Connection();

            string query = "SELECT * FROM credits";
            ObservableCollection<CreditsList> ObservableCollection_CreditsList = new ObservableCollection<CreditsList>();
            SqlCommand command = new SqlCommand(query, connection);
            SqlDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                int credit_id = Convert.ToInt32(reader["credit_id"]);
                string credit_name = Convert.ToString(reader["credit_name"]);
                double credit_percent = Convert.ToDouble(reader["credit_percent"]);
                string credit_info = Convert.ToString(reader["credit_info"]);
                ObservableCollection_CreditsList.Add(new CreditsList(credit_id, credit_name, credit_percent, credit_info));
            }
            reader.Close();
            connection.Close();

            return ObservableCollection_CreditsList;
        }

public class CreditsList
    {
        public CreditsList(int id, string name, double percent, string info)
        {
            this.credit_id = id;
            this.credit_name = name;
            this.credit_percent = percent;
            this.credit_info = info;
        }
        public int credit_id { get; set; }
        public string credit_name { get; set; }
        public double credit_percent { get; set; }
        public string credit_info { get; set; }
    }

public void CreditsList_SelectionChanged(object sender, SelectionChangedEventArgs args)
        {
            MessageBox.Show(Convert.ToString("Что должно быть здесь?"));
        }