private void AddTopicsToPublications(string[] topics)
{
int publicationId = periodicalContext.Publications.OrderByDescending(x => x.PublicationId).First().PublicationId;
List<TopicToPublication> topicsToPublication = new List<TopicToPublication>();
foreach (string item in topics)
{
TopicToPublication newTopicToPublication = new TopicToPublication();
newTopicToPublication.PublicationId = publicationId;
newTopicToPublication.TopicId = periodicalContext.Topics.Where(x => x.TopicName == item).Select(x => x.Id).FirstOrDefault();
periodicalContext.TopicsToPublications.Add(newTopicToPublication);
}
SaveChanges();
}
private void UpdateTopicsToPublications(string[] topics, int publicationId)
{
List<int> oldTopicsId = periodicalContext.TopicsToPublications.Where(x => x.PublicationId == publicationId).Select(x => x.TopicId).ToList();
List<int> newTopicsId = new List<int>();
foreach(string item in topics)
{
int id = periodicalContext.Topics.Where(x => x.TopicName == item).Select(x => x.Id).FirstOrDefault();
newTopicsId.Add(id);
}
//delete topics
foreach(int id in oldTopicsId)
{
if (!newTopicsId.Contains(id))
{
TopicToPublication forDelete = periodicalContext.TopicsToPublications.Where(x => x.TopicId == id && x.PublicationId == publicationId).Select(x => x).FirstOrDefault();
periodicalContext.TopicsToPublications.Remove(forDelete);
}
}
//add new
foreach(int id in newTopicsId)
{
if (!oldTopicsId.Contains(id))
{
TopicToPublication forAdd = new TopicToPublication();
forAdd.PublicationId = publicationId;
forAdd.TopicId = id;
periodicalContext.TopicsToPublications.Add(forAdd);
}
}
SaveChanges();
}