Unfortunately updating object graphs - entities with other related entities - is a rather difficult task and there is no very sophisticated support from Entity Framework to make it easy.
The problem is that setting the state of an entity to Modified
(or generally to any other state) only influences the entity that you pass into DbContext.Entry
and only its scalar properties. It has no effect on its navigation properties and related entities.
You must handle this object graph update manually by loading the entity that is currently stored in the database including the related entities and by merging all changes you have done in the UI into that original graph. Your else
case could then look like this:
//...
else
{
var licenseInDb = ActiveContext.Licenses.Include(l => l.Domains)
.SingleOrDefault(l => l.Id == item.Id)
if (licenseInDb != null)
{
// Update the license (only its scalar properties)
ActiveContext.Entry(licenseInDb).CurrentValus.SetValues(item);
// Delete domains from DB that have been deleted in UI
foreach (var domainInDb in licenseInDb.Domains.ToList())
if (!item.Domains.Any(d => d.Id == domainInDb.Id))
ActiveContext.Domains.Remove(domainInDb);
foreach (var domain in item.Domains)
{
var domainInDb = licenseInDb.Domains
.SingleOrDefault(d => d.Id == domain.Id);
if (domainInDb != null)
// Update existing domains
ActiveContext.Entry(domainInDb).CurrentValus.SetValues(domain);
else
// Insert new domains
licenseInDb.Domains.Add(domain);
}
}
}
ActiveContext.SaveChanges();
//...
You can also try out this project called "GraphDiff" which intends to do this work in a generic way for arbitrary detached object graphs.
The alternative is to track all changes in some custom fields in the UI layer and then evaluate the tracked state changes when the data get posted back to set the appropriate entity states. Because you are in a web application it basically means that you have to track changes in the browser (most likely requiring some Javascript) while the user changes values, adds new items or deletes items. In my opinion this solution is even more difficult to implement.