I’m trying to unit test a custom WPF control using NUnit. The control is

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Asked: May 26, 20262026-05-26T19:45:30+00:00 2026-05-26T19:45:30+00:00

I’m trying to unit test a custom WPF control using NUnit. The control is

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I’m trying to unit test a custom WPF control using NUnit. The control is a ListView of buttons, bound to a list (the DataContext is set up in the control’s constructor).

I’d like to write tests which (e.g.) add items to the list and check that a new button gets added to the view, etc. However, when I add an item to the list in my NUnit test, it still reports that the ListView is empty. Everything works OK when I run my app, though.

I’ve included the relevant code below. What do I need to do to test this?

XAML:

<ListView x:Class="SoundBlock"
          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"
          ItemsSource="{Binding Path=Sounds}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <Button Content="{Binding Title}" />
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

Class definition

public partial class SoundBlock : ListView
{
    public SoundBlock(Board xiBoard)
    {
        // Initialize.
        InitializeComponent();

        // Set the data context for this block.
        DataContext = xiBoard; // Board has an ObservableCollection<Sound> 
                               // property called Sounds.
    }
}

Test case

[Test]
public void TestAddSound()
{
    board = new Board();
    block = new SoundBlock(board);
    Assert.AreEqual(0, block.Items.Count);

    sound = new Sound("sound.mp3");
    board.Sounds.Add(sound);
    Assert.AreEqual(1, block.Items.Count); // This fails - count is still 0
}