DataTable dt;
        NpgsqlDataAdapter adapter;
        NpgsqlConnection conn;
        NpgsqlTransaction tran;

        public void ReadAndFill()
        {
            conn.Open();
            tran = conn.BeginTransaction();

            selcmd.Connection = conn;
            selcmd.Transaction = tran;

            dt.Clear();
            adapter.Fill(dt);
            dgMain.ItemsSource = dt.DefaultView;
            tran.Commit();
            conn.Close();
        }

<TextBox x:Name="textBox" Height="23" TextWrapping="Wrap" Text="{Binding name}" Width="120"/>

        DataContext = dt;
        ReadAndFill();