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Update parent and child collections on generic repository with EF Core

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醉话见心 2020-12-29 14:14

Say I have a Sale class:

public class Sale : BaseEntity //BaseEntity only has an Id  
{        
    public ICollection Items { get;
3条回答
  • 自闭症患者
    自闭症患者 (楼主)
    2020-12-29 15:09

    @craigmoliver Here's my solution. It is not the best, I know - if you find a more elegant way, please share.

    Repository:

    public async Task UpdateAsync(TEntity entity, bool save = true, params Expression>[] navigations)
            where TEntity : class, IIdEntity
        {
            TEntity dbEntity = await _context.FindAsync(entity.Id);

        EntityEntry dbEntry = _context.Entry(dbEntity);
        dbEntry.CurrentValues.SetValues(entity);

        foreach (Expression> property in navigations)
        {
            var propertyName = property.GetPropertyAccess().Name;
            CollectionEntry dbItemsEntry = dbEntry.Collection(propertyName);
            IClrCollectionAccessor accessor = dbItemsEntry.Metadata.GetCollectionAccessor();

            await dbItemsEntry.LoadAsync();
            var dbItemsMap = ((IEnumerable)dbItemsEntry.CurrentValue)
                .ToDictionary(e => string.Join('|', _context.FindPrimaryKeyValues(e)));

            foreach (var item in (IEnumerable)accessor.GetOrCreate(entity))
            {
                if (!dbItemsMap.TryGetValue(string.Join('|', _context.FindPrimaryKeyValues(item)), out object oldItem))
                {
                    accessor.Add(dbEntity, item);
                }
                else
                {
                    _context.Entry(oldItem).CurrentValues.SetValues(item);
                    dbItemsMap.Remove(string.Join('|', _context.FindPrimaryKeyValues(item)));
                }
            }

            foreach (var oldItem in dbItemsMap.Values)
            {
                accessor.Remove(dbEntity, oldItem);
                await DeleteAsync(oldItem as IEntity, false);

            }
        }

        if (save)
        {
            await SaveChangesAsync();
        }

        return entity;
    }



    Context:
    


     public IReadOnlyList FindPrimaryKeyProperties(T entity)
        {
            return Model.FindEntityType(entity.GetType()).FindPrimaryKey().Properties;
        }

        public IEnumerable FindPrimaryKeyValues(TEntity entity) where TEntity : class
        {
            return from p in FindPrimaryKeyProperties(entity)
                   select entity.GetPropertyValue(p.Name);
        }

    
    
             
    
                                                        
    
            
            
    
              
                
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