Accèder à une base Access via OleDb

Le singleton utilisé pour la connexion

public class Sql

       {

             private static Sql _instance;

             private OleDbConnection connection;

             private static object locker = new object();

             public ConnectionStringSettings ConnectionStringSettings { get; set; }

             private Sql() { }

             public static Sql Instance

             {

                    get

                    {

                           lock (locker)

                           {

                                  if (_instance == null)

                                  _instance = new Sql();

                           }

                           return _instance;

                    }

             }

             public OleDbConnection GetConnection()

             {

                    if (connection == null)

                    {

                           ConnectionStringSettings = ConfigurationManager.ConnectionStrings["dbConnectionString"];

                           connection = new OleDbConnection();

                    }

            connection.ConnectionString = ConnectionStringSettings.ConnectionString;

                    if (connection.State == ConnectionState.Closed)

                           connection.Open();

                    return connection;

             }

       }

La classique classe Client

public class Client          

{

        public int Id { get; set; }

        public string Name { get; set; }

        public string Email { get; set; }

        public int CategoryId { get; set; }

}