So, I finally managed to get it working, although not fully automatically.
Notice the AutoMapper <3. It handles all the mapping of properties so you don't have to do it manually. Also, if used in a way where it maps from one object to another, then it only updates the properties and that marks changed properties as Modified to EF, which is what we want.
If you would use explicit context.Update(entity), the difference would be that entire object would be marked as Modified and EVERY prop would be updated.
In that case you don't need tracking but the drawbacks are as mentioned.
Maybe that's not a problem for you but it's more expensive and I want to log exact changes inside Save so I need correct info.
// We always want tracking for auto-updates
var entityToUpdate = unitOfWork.GetGenericRepository<Article, int>()
.GetAllActive() // Uses EF tracking
.Include(e => e.Barcodes.Where(e => e.Status == DatabaseEntityStatus.Active))
.First(e => e.Id == request.Id);
mapper.Map(request, entityToUpdate); // Maps it to entity with AutoMapper <3
ModifyBarcodes(entityToUpdate, request);
// Removed part of the code for space
unitOfWork.Save();
ModifyBarcodes part here.
We want to modify our collection in a way that EF tracking won't end up messed up.
AutoMapper mapping would, unforunately, create a completely new instance of collection, there fore messing up the tracking, although, I was pretty sure it should work.
Anyways, since I'm sending complete list from FE, here we actually determine what should be Added/Updated/Deleted and just handle the list itself.
Since EF tracking is ON, EF handles it like a charm.
var toUpdate = article.Barcodes
.Where(e => articleDto.Barcodes.Select(b => b.Id).Contains(e.Id))
.ToList();
toUpdate.ForEach(e =>
{
var newValue = articleDto.Barcodes.FirstOrDefault(f => f.Id == e.Id);
mapper.Map(newValue, e);
});
var toAdd = articleDto.Barcodes
.Where(e => !article.Barcodes.Select(b => b.Id).Contains(e.Id))
.Select(e => mapper.Map<Barcode>(e))
.ToList();
article.Barcodes.AddRange(toAdd);
article.Barcodes
.Where(e => !articleDto.Barcodes.Select(b => b.Id).Contains(e.Id))
.ToList()
.ForEach(e => article.Barcodes.Remove(e));
CreateMap<ArticleDto, Article>()
.ForMember(e => e.DateCreated, opt => opt.Ignore())
.ForMember(e => e.DateModified, opt => opt.Ignore())
.ForMember(e => e.CreatedById, opt => opt.Ignore())
.ForMember(e => e.LastModifiedById, opt => opt.Ignore())
.ForMember(e => e.Status, opt => opt.Ignore())
// When mapping collections, the reference itself is destroyed
// hence f* up EF tracking and makes it think all previous is deleted
// Better to leave it on manual and handle collecion manually
.ForMember(e => e.Barcodes, opt => opt.Ignore())
.ReverseMap()
.ForMember(e => e.Barcodes, opt => opt.MapFrom(src => src.Barcodes.Where(e => e.Status == DatabaseEntityStatus.Active)));
