Question

I have class Person:

    public class Person : INotifyPropertyChanged
    {

        private String name = "";
        public event PropertyChangedEventHandler PropertyChanged;

        public Person()
        {
            NameProperty = "hi";
        }

        public Person(String _name)
        {
            NameProperty = _name;
        }

        public String NameProperty
        {
            get { return name; }
            set 
            { 
                name = value;
                OnPropertyChanged("NameProperty");
            }
        }

        public override String ToString()
        {
            return NameProperty;
        }

        protected void OnPropertyChanged(string name)
        {

            PropertyChangedEventHandler handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(name));
            }

        }

    }

And I can bind the instance of my class to TextBox:

myPerson = new Person("demas");
Binding myBinding = new Binding("NameProperty");
myBinding.Source = myPerson;
txtName.SetBinding(TextBox.TextProperty, myBinding);

Now I have collection of my class and want to bind it to ListBox:

List<Person> myCollection = new List<Person>(); // on the MainWindow level

myCollection.Add(new Person("one"));
myCollection.Add(new Person("two"));
myCollection.Add(new Person("three"));

So I have to see in the ListBox three values: one, two, three. How can I do it?

Answer 1

Expose your collection as a public property in your MainWindow. If you want your ListBox to get updated when elements are added or removed to your collection, you should use an ObservableCollection<T> rather than List<T>.

readonly ObservableCollection<Person> myCollection = new ObservableCollection<Person>();

public ObservableCollection<Person> MyCollection
{
    get { return myCollection; }
} 

Then, in your XAML, use data binding to reference the property:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:l="clr-namespace:WpfApplication1"
        xmlns:p="clr-namespace:WpfApplication1.Properties"
        DataContext="{Binding RelativeSource={RelativeSource Self}}"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <ListBox ItemsSource="{Binding MyCollection}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding NameProperty}" />
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

Don’t forget to set the DataContext either on your ListBox or on its parent window.

P.S. Identifier names should identify the purpose, not the type. Use Persons instead of MyCollection; use Name instead of NameProperty.