I've a unit test of the above method, it works correctly with List<T> for example, now I changed the implementation calling the ToArray but the problem is the same.
For now I solved cloning the entity using the BinaryFormatter, but clearly is not the final solution. Any idea? Thanks! Matteo On Thursday, July 4, 2013 5:11:30 PM UTC+2, PeteA wrote: > > Change > var toRemove = firstCollection.Where(item => > secondCollection.All(x => x.Key != item.Key)); > to > var toRemove = firstCollection.Where(item => > secondCollection.All(x => x.Key != item.Key)).ToArray(); > > As it stands, your code is lazily iterating toRemove; as soon as > something's removed from it, you'll get exception you described. This is > not related to NHibernate, it's a standard 'feature' of .NET :). > > /Pete > > -----Original Message----- > From: [email protected] <javascript:> on behalf of Matteo Migliore > Sent: Thu 7/4/2013 11:58 AM > To: [email protected] <javascript:> > Subject: [nhusers] Modify the collections of an entity "collection was > modified" exception > > Hi, > > I obtain the error "Collection was modified; enumeration operation may not > execute." when I try to save (merge) > a loaded entity. > > I use AutoMapper to write the values from the DTO (command) to the loaded > entity and this method to synchronize > the collection between the entity and the command: > > public static ICollection<TFirst> Synchronize<TFirst, TSecond>( > this ICollection<TFirst> first, > IEnumerable<TSecond> second, > Func<TSecond, TFirst> convert = null, > Func<TFirst, int> firstHash = null, > Func<TSecond, int> secondHash = null) > { > if (firstHash == null) > { > firstHash = x => x.GetHashCode(); > } > > if (secondHash == null) > { > secondHash = x => x.GetHashCode(); > } > > if (convert == null) > { > convert = x => Mapper.Map<TFirst>(x); > } > > var firstCollection = first.ToDictionary(x => firstHash(x), x => > x); > var secondCollection = second.ToDictionary(x => secondHash(x), x > => x); > > var toAdd = secondCollection.Where(item => firstCollection.All(x > => x.Key != item.Key)).Select(x => convert(x.Value)); > > foreach (var item in toAdd) > { > first.Add(item); > } > > var toRemove = firstCollection.Where(item => > secondCollection.All(x => x.Key != item.Key)); > > foreach (var item in toRemove) > { > first.Remove(item.Value); > } > > return first; > } > > How can I fix the problem? > > Thanks, > Matteo > > -- > You received this message because you are subscribed to the Google Groups > "nhusers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > To post to this group, send email to [email protected] <javascript:>. > > Visit this group at http://groups.google.com/group/nhusers. > For more options, visit https://groups.google.com/groups/opt_out. > > > > -- You received this message because you are subscribed to the Google Groups "nhusers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/nhusers. For more options, visit https://groups.google.com/groups/opt_out.
