public void UpdateArticle(int id)
{
var authorList = SelectedAuthor.Select(a => new Author {
Id = a.Id
}).ToList();
var categoriesList = SelectedCategory.Select(c => new Category {
Id = c.Id, Name = c.Name
}).ToList();
Article newArticle = new Article()
{
Id = id,
Title = Title,
Preamble = Preamble,
ArticleBody = ArticleBody,
Categories = categoriesList.ToArray(),
Authors = authorList.ToArray(),
UpdatedDate = DateTime.Now
};
client.UpdateArticle(newArticle);
}