public static async Task UpdateGalleryAsync(this SQLiteDatabase database, IPictureGallery gallery)
{
if (!gallery.Id.HasValue)
{
// If the gallery doesn't have an ID, assume that it's new, and attempt to add it.
await database.AddGalleryAsync(gallery);
}
else
{
// Update the gallery in the database.
IPictureGallery oldGallery = await database.GetGalleryAsync(gallery.Id);
IEnumerable <IPicture> deletedPictures = oldGallery.Where(oldPicture => !gallery.Any(picture => oldPicture.Id == picture.Id));
IEnumerable <IPicture> newPictures = gallery.Where(picture => !oldGallery.Any(oldPicture => picture.Id == oldPicture.Id));
foreach (IPicture picture in deletedPictures)
{
await database.RemovePictureAsync(gallery, picture);
}
foreach (IPicture picture in newPictures)
{
await database.AddPictureAsync(gallery, picture);
}
}
}