Assembly Trimming Issues with .NET7 and Avalonia UI v11

Question

I'm deploying my .NET7 application using Assembly Trimming and am working around the trimming issues.

There's this weird issue with the list of files of type ICollectionView<FileItem>. The list items appear but only the text is missing, otherwise the app seems to work fine. Other listboxes are displaying fine.

public class FileItem
{
    public FileItem() : this(string.Empty, string.Empty)
    { }

    public FileItem(string name, string path)
    {
        Name = name;
        Path = path;
    }
    
    public string Name { get; set; }
    public string Path { get; set; }
}

Another issue is with serialization, I serialize to a settings file that contains this.

public List<SettingsPlaylistItem> Playlists { get; set; } = new();

It complains that SettingsPlaylistItem constructor is missing. Adding [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] does not help.

The only solution I found is to add this on app start. Is there a better solution?

// Solve trimming problems
var _ = new SettingsPlaylistItem();

Answer 1

First, setting the first line on Main method works, but setting the 2nd on the type itself doesn't. Not sure why.

// Works
[DynamicDependency(DynamicallyAccessedMemberTypes.All, typeof(FileItem))]
public static void Main(string[] args) { }

// Does not work
[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
public class FileItem
{
    public FileItem() : this(string.Empty, string.Empty)
    { }

    public FileItem(string name, string path)
    {
        Name = name;
        Path = path;
    }
    
    public string Name { get; set; }
    public string Path { get; set; }
}

Then, a better way to deal with serialization issues is to use XML Serializer Source Generation. As a note, JSon Source Generator implementation is a lot better than for XML. Using Json Source Generator, I could remove the above attributes, and trim XML support out of the app for a nice file size reduction, plus faster initialization.

I also ran into another issue of a list that wouldn't display and none of the above worked. If adding items to an ObservableCollection from a background threat, it works without trimming, but fails with trimming! The solution was to invoke the Add onto the UI threat.

I guess that there are few discussions on the topic because WPF does not support trimming. Avalonia11 supports it but it's still in preview5.