I’m learning ReactiveUI at the moment, and I’m struggling to figure out how to bind a collection to a ListBox in WPF. I already understand the MVVM pattern, and I was able to do this very thing in MVVM Light some years ago, but ReactiveUI is proving more difficult. I haven’t been able to find too many simple examples, just convoluted ones that don’t do a great job at demonstrating the basics. Also, a lot of the answers I’ve found on Stack Overflow are very old, so they don’t use the new Dynamic Data libraries that ReactiveUI recommends nowadays.

I’m working in a very simple WPF application while I try to learn the ropes.
I have a simple view called TextBlockView:

<rxui:ReactiveUserControl x:Class="MvvmSandbox.Views.TextBlockView"
             x:TypeArguments="vm:TextBlockViewModel"
             xmlns:rxui="http://reactiveui.net"
             xmlns:vm="clr-namespace:MvvmSandbox.ViewModels"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:MvvmSandbox.Views"
             mc:Ignorable="d" 
             d:DesignHeight="250" d:DesignWidth="500">
    <TextBlock x:Name="String" HorizontalAlignment="Center" VerticalAlignment="Center" />
</rxui:ReactiveUserControl>

Here’s the code-behind:

using MvvmSandbox.ViewModels;
using ReactiveUI;
using System.Reactive.Disposables;

namespace MvvmSandbox.Views
{
    public partial class TextBlockView : ReactiveUserControl<TextBlockViewModel>
    {
        public TextBlockView()
        {
            InitializeComponent();
            ViewModel = new TextBlockViewModel();

            this.WhenActivated(disposable =>
            {
                this.Bind(ViewModel, vm => vm.String, v => v.String.Text)
                    .DisposeWith(disposable);
            });
        }
    }
}

And here’s the view model:

using ReactiveUI;
using System.Collections.ObjectModel;

namespace MvvmSandbox.ViewModels
{
    public class ListBoxViewModel : ReactiveObject
    {
        public ObservableCollection<string> Strings => _strings;
        private ObservableCollection<string> _strings;

        public ListBoxViewModel()
        {
            _strings = new ObservableCollection<string>()
            {
                "This is a test of the Emergency Broadcast System.",
                "This is only a test."
            };
        }
    }
}

The view does come out with the items, but they’re collapsed to their minimum height and don’t display the strings themselves; you can see the blue bounding box for the first item here.