public async Task <ImagePost> Update(int id, string description, IEnumerable <Tag> tags)
{
using (ShowNTellDbContext context = _contextFactory.CreateDbContext())
{
ImagePost storedImagePost = await context.ImagePosts
.Include(p => p.Tags)
.ThenInclude(t => t.Tag)
.FirstOrDefaultAsync(p => p.Id == id);
if (storedImagePost == null)
{
throw new EntityNotFoundException <int>(id);
}
// Update the description.
storedImagePost.Description = description;
// Update the tags.
ICollection <ImagePostTag> mergedTags = null;
if (tags != null)
{
// Remove all old tags.
context.Set <ImagePostTag>().RemoveRange(storedImagePost.Tags);
// Set the new tags.
mergedTags = await GetMergedNewAndExistingTagsFromContext(tags, context);
storedImagePost.Tags = ConvertImagePostTagsForSave(mergedTags);
}
context.Update(storedImagePost);
await context.SaveChangesAsync();
// Set the tags to the fully populated tags.
if (mergedTags != null)
{
storedImagePost.Tags = mergedTags;
}
return(storedImagePost);
}
}