EF-局部更新

//
////1
public Task ReservedQuantity(long productId, long skuId, int reservedQuantity, long userId) {
    return Update<Inventory>(i => new Inventory {
        ReservedQuantity = i.ReservedQuantity + reservedQuantity,
        AvaliableQuantity = i.AvaliableQuantity - reservedQuantity,
        LastModifiedTime = DateTimeOffset.Now,
        LastModifiedUserId = userId
    }, i => i.SkuId == skuId);

}

protected Task<bool> Add<TModel>(TModel entity, Expression<Func<TModel, bool>> existsChecker = null) where TModel : class, IEntity {
    return _context.Add(entity, existsChecker);

}

protected Task<int> Update<TModel>(Expression<Func<TModel, TModel>> updateProperties, Expression<Func<TModel, bool>> @where) where TModel : class, IEntity {
    return _context.Update(updateProperties, @where);

}

protected Task<int> Delete<TModel>(Expression<Func<TModel, bool>> @where) where TModel : class, IEntity {
    return _context.Delete(@where);

}
--//2

public void Update(T obj, params Expression<Func<T, object>>[] propertiesToUpdate)
{
    Context.Set<T>().Attach(obj);

    foreach (var p in propertiesToUpdate)
    {
        Context.Entry(obj).Property(p).IsModified = true;
    }
}
And then to call, for example:

public void UpdatePasswordAndEmail(long userId, string password, string email)
{
    var user = new User {UserId = userId, Password = password, Email = email};

    Update(user, u => u.Password, u => u.Email);

    Save();
}

public interface IRepository
{
    void Update<T>(T obj, params Expression<Func<T, object>>[] propertiesToUpdate) where T : class;
}

public class Repository : DbContext, IRepository
{
    public void Update<T>(T obj, params Expression<Func<T, object>>[] propertiesToUpdate) where T : class
    {
        Set<T>().Attach(obj);
        propertiesToUpdate.ToList().ForEach(p => Entry(obj).Property(p).IsModified = true);
        SaveChanges();
    }
}

//3

 public int Update(TEntity entity)
        {
            dbcontext.Set<TEntity>().Attach(entity);
            PropertyInfo[] props = entity.GetType().GetProperties();
            foreach (PropertyInfo prop in props)
            {
                if (prop.GetValue(entity, null) != null)
                {
                    if (prop.GetValue(entity, null).ToString() == "&nbsp;")
                        dbcontext.Entry(entity).Property(prop.Name).CurrentValue = null;
                    dbcontext.Entry(entity).Property(prop.Name).IsModified = true;
                }
            }
            return dbcontext.SaveChanges();
        }