基于导航属性的orderBy动态实现方法

Question

var query = TableNoTracking;
query = query
            .Include(r => r.UserRoles).ThenInclude(o => o.Role)
            .Include(c => c.Photos.Where(x => x.IsMain))
            .Include(w => w.Wallets);

我的排序部分如下所示，我需要动态处理排序。

   if (!string.IsNullOrWhiteSpace(filterUser.SortBy))
            {
                switch (filterUser.Reverse)
                {
                    //reverse
                    case true:
                        switch (filterUser.SortBy)
                        {
                            case UserNavigationPropsForSort.InventorySum:
                                query = query.OrderByDescending(x => x.Wallets.Select(y => y.Inventory).Sum());
                                break;
                            case UserNavigationPropsForSort.InterMoneySum:
                                query = query.OrderByDescending(x => x.Wallets.Select(y => y.InterMoney).Sum());
                                break;
                            case UserNavigationPropsForSort.ExitMoneySum:
                                query = query.OrderByDescending(x => x.Wallets.Select(y => y.ExitMoney).Sum());
                                break;
                            case UserNavigationPropsForSort.OnExitMoneySum:
                                query = query.OrderByDescending(x => x.Wallets.Select(y => y.OnExitMoney).Sum());
                                break;
                        }

                        break;
                    case false:
                        switch (filterUser.SortBy)
                        {
                            case UserNavigationPropsForSort.InventorySum:
                                query = query.OrderBy(x => x.Wallets.Select(y => y.Inventory).Sum());
                                break;
                            case UserNavigationPropsForSort.InterMoneySum:
                                query = query.OrderBy(x => x.Wallets.Select(y => y.InterMoney).Sum());
                                break;
                            case UserNavigationPropsForSort.ExitMoneySum:
                                query = query.OrderBy(x => x.Wallets.Select(y => y.ExitMoney).Sum());
                                break;
                            case UserNavigationPropsForSort.OnExitMoneySum:
                                query = query.OrderBy(x => x.Wallets.Select(y => y.OnExitMoney).Sum());
                                break;
                        }
                        break;
                }
            }

我包括几个实体，现在我想根据包含的属性(例如钱包中的库存)动态地排序这个查询。我尝试了动态linq库，但它不适用于这种情况；

我该怎么做？

Answer 1

信贷@nbokman和@Svyatoslav Danyliv。我用表达式代替Func，现在使用代码工作。

        if (!string.IsNullOrWhiteSpace(filterUser.SortBy))
            {
                if (filterUser.SortableProperties.Any(x =>
                    string.Equals(x, filterUser.SortBy, StringComparison.CurrentCultureIgnoreCase)))
                {
                    Expression<Func<User, int>> exp = filterUser.SortBy switch
                    {
                        UserNavigationPropsForSort.InventorySum => w => w.Wallets.Select(x => x.Inventory).Sum(),
                        UserNavigationPropsForSort.InterMoneySum => w => w.Wallets.Select(x => x.InterMoney).Sum(),
                        UserNavigationPropsForSort.ExitMoneySum => w => w.Wallets.Select(x => x.ExitMoney).Sum(),
                        UserNavigationPropsForSort.OnExitMoneySum => w => w.Wallets.Select(x => x.OnExitMoney).Sum(),
                        _ => throw new ArgumentOutOfRangeException()
                    };

                    query = filterUser.Reverse ? query.OrderByDescending(exp) : query.OrderBy(exp);
                }
            }

Answer 2

我不能完全确定在不设置UserNavigationPropsForSort和Wallet属性之间的映射的情况下完全动态地完成它。

• ，除非您想进入表达式树构建，否则我怀疑它对您实际要做的工作来说是过分的。如果没有，请参考此处的docs：https://learn.microsoft.com/en-us/dotnet/csharp/expression-trees-building

我所做的是使您的代码更加简洁和可扩展：

            var query = TableNoTracking;
            query = query
                .Include(r => r.UserRoles).ThenInclude(o => o.Role)
                .Include(c => c.Photos.Where(x => x.IsMain))
                .Include(w => w.Wallets);
            
            if (!string.IsNullOrWhiteSpace(filterUser.SortBy.ToString()))
            {
                Func<Wallet, decimal> sortByToProperty = filterUser.SortBy switch
                {
                    UserNavigationPropsForSort.InventorySum => w => w.Inventory,
                    UserNavigationPropsForSort.InterMoneySum => w => w.InterMoney,
                    UserNavigationPropsForSort.ExitMoneySum => w => w.ExitMoney,
                    UserNavigationPropsForSort.OnExitMoneySum => w => w.OnExitMoney,
                    _ => throw new ArgumentOutOfRangeException()
                };

                query = filterUser.Reverse
                    ? query.OrderByDescending(x => x.Wallets.Select(sortByToProperty).Sum())
                    : query.OrderBy(x => x.Wallets.Select(sortByToProperty).Sum());
            }

如果在任何时候想要添加更多要排序的属性，则可以展开sortByToProperty开关。

如果这是你的意思请告诉我。