datamanager

    public class DataManager : IDataManager
    {
        public DbDataAdapter DataAdapter { get; set; }
        public DbConnection Connection { get; set; }
        public DbProviderFactory Factory { get; set; }

        public DataManager(string providerName)
        {
            var connectionString = GetConnectionStringByProvider(providerName);
            CreateDbConnection(providerName, connectionString);
        }

        public string GetConnectionStringByProvider(string providerName)
        {
            // Return null on failure.
            string returnValue = null;

            // Get the collection of connection strings.
            ConnectionStringSettingsCollection settings = ConfigurationManager.ConnectionStrings;

            // Walk through the collection and return the first
            // connection string matching the providerName.
            if (settings != null)
            {
                foreach (ConnectionStringSettings cs in settings)
                {
                    if (Equals(cs.ProviderName.ToLower(), providerName.ToLower()))
                    {
                        returnValue = cs.ConnectionString;
                        break;
                    }
                }
            }

            return returnValue;
        }

        public void CreateDbConnection(string providerName, string connectionString)
        {
            // Create the DbProviderFactory and DbConnection.
            if (connectionString != null)
            {
                try
                {
                    var dbpf = DbProviderFactories.GetFactory(providerName);

                    this.Connection = dbpf.CreateConnection();
                    this.Connection.ConnectionString = connectionString;
                    this.DataAdapter = dbpf.CreateDataAdapter(); // returns 0
                    this.Factory = dbpf;
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }
    }