#967 – ListBox Data Binding Basics, part IV

In the earlier posts, we created an Actor class and then populated a list with a series of Actor objects.  We can now bind a ListBox to this list using its ItemsSource property.

    <StackPanel>
        <ListBox Margin="15" Width="250" Height="250"
                 ItemsSource="{Binding ActorList}"
                 DisplayMemberPath="NameAndDates"
                 SelectedItem="{Binding SelectedActor}"/>
        <Label Margin="10,0" Content="{Binding SelectedActor.KnownFor}"/>
    </StackPanel>

The ItemsSource property indicates that we want the ListBox filled with elements from our ActorList property, which is a collection of Actor objects.

The DisplayMemberPath property indicates that each entry in the list should be rendered as a string using the Actor.NameAndDates property.

The SelectedItem property indicates that when a user selects an item, our SelectedActor property should be set to refer to the selected Actor instance.  We demonstrate that by binding a Label element to a property of that selected actor.

#966 – ListBox Data Binding Basics, part III

Assume that we want to use a ListBox to display a list of actors and that we have an Actor type to store all the information for a single actor.

Our next step is to create a collection of Actor instances that we’ll then be able to bind to.  Below is the code-behind for a simple WPF application that creates a collection of Actor instances and stores them in an ActorList property.  We also set up a SelectedActor property that will use data binding to reflect the actor that the user has currently selected.

    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public MainWindow()
        {
            this.InitializeComponent();
            this.DataContext = this;

            ActorList = new ObservableCollection<Actor>
            {
                new Actor("Ginger Rogers", 1911, 1995, "Kitty Foyle",
                    new Uri("ActressImages/GingerRogers.jpg", UriKind.Relative)),
                new Actor("Joan Fontaine", 1917, null, "Suspicion",
                    new Uri("ActressImages/JoanFontaine.jpg", UriKind.Relative)),
                new Actor("Greer Garson", 1904, 1996, "Mrs. Miniver",
                    new Uri("ActressImages/GreerGarson.jpg", UriKind.Relative)),
                new Actor("Jennifer Jones", 1919, 2009, "The Song of Bernadette",
                    new Uri("ActressImages/JenniferJones.jpg", UriKind.Relative)),
                new Actor("Ingrid Bergman", 1915, 1982, "Gaslight",
                    new Uri("ActressImages/IngridBergman.jpg", UriKind.Relative)),
                new Actor("Joan Crawford", 1904, 1977, "Mildred Pierce",
                    new Uri("ActressImages/JoanCrawford.jpg", UriKind.Relative)),
                new Actor("Olivia de Havilland", 1916, null, "To Each His Own",
                    new Uri("ActressImages/OliviaDeHavilland.jpg", UriKind.Relative)),
                new Actor("Loretta Young", 1913, 2000, "The Farmer's Daughter",
                    new Uri("ActressImages/LorettaYoung.jpg", UriKind.Relative)),
                new Actor("Jane Wyman", 1917, 2007, "Johnny Belinda",
                    new Uri("ActressImages/JaneWyman.jpg", UriKind.Relative)),
                new Actor("Judy Holliday", 1921, 1965, "Born Yesterday",
                    new Uri("ActressImages/JudyHolliday.jpg", UriKind.Relative))
            };
        }

        private ObservableCollection<Actor> actorList;
        public ObservableCollection<Actor> ActorList
        {
            get { return actorList; }
            set
            {
                if (value != actorList)
                {
                    actorList = value;
                    RaisePropertyChanged("ActorList");
                }
            }
        }

        private Actor selectedActor;
        public Actor SelectedActor
        {
            get { return selectedActor; }
            set
            {
                if (value != selectedActor)
                {
                    selectedActor = value;
                    RaisePropertyChanged("SelectedActor");
                }
            }
        }

        // INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        private void RaisePropertyChanged(string propName)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }
    }

#965 – ListBox Data Binding Basics, part II

Assume that we want to use a ListBox to display a list of actors.  We can start by creating an Actor type that stores various information about an actor.  We want the class to implement the INotifyPropertyChanged interface, so that data binding client are notified of changes to any properties.

Full code for Actor.cs is shown below.  Note that when we change FullName, BirthYear or DeathYear properties, we also flag the derived NameAndDates property as potentially changed.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;

namespace WpfApplication2
{
    public class Actor : INotifyPropertyChanged
    {
        public Actor()
        {
        }

        public Actor(string fullName, int? birthYear, int? deathYear, string knownFor, Uri image)
        {
            FullName = fullName;
            BirthYear = birthYear;
            DeathYear = deathYear;
            KnownFor = knownFor;
            Image = image;
        }

        private string fullName;
        public string FullName
        {
            get { return fullName; }
            set
            {
                fullName = value;
                RaisePropertyChanged("FullName");
                RaisePropertyChanged("NameAndDates");
            }
        }

        private int? birthYear;
        public int? BirthYear
        {
            get { return birthYear; }
            set
            {
                birthYear = value;
                RaisePropertyChanged("BirthYear");
                RaisePropertyChanged("NameAndDates");
            }
        }

        private int? deathYear;
        public int? DeathYear
        {
            get { return deathYear; }
            set
            {
                deathYear = value;
                RaisePropertyChanged("DeathYear");
                RaisePropertyChanged("NameAndDates");
            }
        }

        private string knownFor;
        public string KnownFor
        {
            get { return knownFor; }
            set
            {
                knownFor = value;
                RaisePropertyChanged("KnownFor");
            }
        }

        private Uri image;
        public Uri Image
        {
            get { return image; }
            set
            {
                image = value;
                RaisePropertyChanged("Image");
            }
        }

        public string NameAndDates
        {
            get
            {
                string result = FullName;

                if (BirthYear.HasValue)
                {
                    if (DeathYear.HasValue)
                        result = result + string.Format(" ({0}-{1})", BirthYear.Value, DeathYear.Value);
                    else
                        result = result + string.Format(" ({0}- )", BirthYear.Value);
                }

                return result;
            }
        }

        // INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        private void RaisePropertyChanged(string propName)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }
    }
}