UmbracoGuidUdiUriExtensions.cs

public static class UriStringExtensions
{
    public static Uri? ToUri(this string? uriString, UriKind uriKind = UriKind.RelativeOrAbsolute)
    {
        if (string.IsNullOrWhiteSpace(uriString)) return null;

        return Uri.TryCreate(uriString, uriKind, out var uri) ? uri : null;
    }
    
    public static IEnumerable<Uri> ToUriCollection(this string? uriCollectionString,  char separator = ',', UriKind uriKind = UriKind.RelativeOrAbsolute)
    {
        if (string.IsNullOrWhiteSpace(uriCollectionString)) return [];

        var uriStringCollection = uriCollectionString.Split(separator, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);

        return uriStringCollection.Select(uriString => uriString
            .ToUri(uriKind))
            .Where(uri => uri is not null)
            .Select(uri => uri!);
    }
    
    public static GuidUdi? ToGuidUdi(this string? guidUdiUriString)
    {
        return guidUdiUriString
            .ToUri()
            .ToGuidUdi();
    }
    
    public static IEnumerable<GuidUdi> ToGuidUdiCollection(this string? guidUdiUriStringCollection, char separator = ',')
    {
        return guidUdiUriStringCollection
            .ToUriCollection(separator)
            .Select(guidUdiUri => guidUdiUri.ToGuidUdi())
            .Where(guidUdi => guidUdi is not null)
            .Select(guidUdi => guidUdi!);
    }
    
    public static IEnumerable<Guid> ToGuidCollection(this string? guidUdiUriStringCollection, char separator = ',')
    {
        return guidUdiUriStringCollection.ToGuidUdiCollection(separator).Select(guidUdi => guidUdi.Guid);

    }
}

public static class GuidUdiUriExtensions
{
    public static GuidUdi? ToGuidUdi(this Uri? guidUdiUri)
    {
        return guidUdiUri is not { Scheme: "umb"} ? null : new GuidUdi(guidUdiUri);
    }
}

public static class GuidUdiExtensions
{
    public static IEnumerable<Guid> ToGuidCollection(this IEnumerable<GuidUdi?> guidUdiCollection)
    {
        return guidUdiCollection
            .Where(guidUdi => guidUdi is not null)
            .Select(guidUdi => guidUdi!.Guid);
    }    
}