Olav Tollefsen's Blog

Windows Presentation Foundation (Avalon) Databinding to objects

Databinding to an object datasource is really simple in Windows Presentation Foundation. I didn't find any good samples around, so I'm posting some code here to help you save some time.

My scenarion is really simple, I would like to create an WPF application to visualize my DVD collection. The code also shows how to bind an Image control i WPF to an JPEG image stored inside the SQL Server database (not just a pointer to a file). The code is simplified to only illustrate the main concepts and I have not worked with the design part yet.

First I start with a class to represent the information about a DVD title:

    public class Dvd
    {

        int _dvdId;
        private string _title;
        private byte[] _frontCover;

        public int Id { get { return _dvdId; } }

        public string Title { get { return _title; } }

        public BitmapFrame FrontCover
        {
            get
            {
                BitmapFrame frontCover = System.Windows.Media.Imaging.BitmapFrame.Create(new System.IO.MemoryStream(_frontCover));

                return frontCover;
            }
        }

        public Dvd(
            int id,
            string title,
            byte[] frontCover)
        {
            _dvdId = id;
            _title = title;
            _frontCover = frontCover;
        }

    }

The Data Access Layer contains a method to return a list DVD's from the database:

        public static List<Dvd> GetTitles()
        {
            OdbcConnection connection = new OdbcConnection(m_connectionString);

            string selectCommand = @"
                SELECT     DvdId, Title, FrontCover
                FROM         Titles";

            OdbcCommand command = new OdbcCommand(selectCommand, connection);

            List<Dvd> titles = new List<Dvd>();

            connection.Open();
            OdbcDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                Dvd dvd = new Dvd(
                    Convert.ToInt32(reader["DvdId"]),
                    Convert.ToString(reader["Title"]),
                    (byte[])reader["FrontCover"]);

                titles.Add(dvd);

            }

            return titles;
        }

Then we have the DvdCollection class which includes a method to return a list of Dvd objects:

using System;
using System.Collections.Generic;
using System.Text;
using DvdLibrary.BusinessEntities;
using DvdLibrary.DataAccessLayer;

namespace DvdLibrary.BusinessLogicLayer
{
    public class DvdCollection
    {
        public static List<Dvd> GetTitles()
        {
            return TitlesDAL.GetTitles();
        }

    }
}

Then in the XAML code-behind, I have this code to retrieve a a list of DVD titles from the business logic layer:

private void OnInit(object sender, EventArgs e)
{
    List<Dvd> titles = DvdCollection.GetTitles();

    DvdList.DataContext = titles;
}

Finally we have the XAML file showing how to do the Databind to the list of DVD titles using a ListBox:

 <Grid.Triggers>
  <EventTrigger RoutedEvent="FrameworkElement.Loaded">
   <EventTrigger.Actions>
    <BeginStoryboard x:Name="OnLoaded_BeginStoryboard" Storyboard="{DynamicResource OnLoaded}"/>
   </EventTrigger.Actions>
  </EventTrigger>
 </Grid.Triggers>
 
 <ColumnDefinition/>
 <RowDefinition/>
 <ListBox
  IsSynchronizedWithCurrentItem="True"
  x:Name="DvdList"
  Margin="19,23,41,16"
  Width="Auto"
  Height="Auto"
  RenderTransformOrigin="0.5,0.5"
  ItemsSource="{Binding}"
  ItemTemplate="{StaticResource DvdItemTemplate}"
  />
</Grid>