public void AddOrUpdateArticle(ArticleEntity newEntity)
{
ArticleEntity oldEntity = ArticleList.FirstOrDefault <ArticleEntity>(p => p.ArticleNo == newEntity.ArticleNo);
if (oldEntity == null)
{
ArticleList.Insert(0, newEntity);
}
else
{
int index = ArticleList.IndexOf(oldEntity);
ArticleList.Remove(oldEntity);
ArticleList.Insert(index, newEntity);
}
ArticleList = new List <ArticleEntity>(_articleList);
}