如何筛选子集合使用LINQ动态 [英] How to filter child collection with linq dynamic

问题描述

我尝试过滤用户请求的结果。
例如，您有订单和订单详情和产品是子集合。

I'm trying to filter results for user request. For instance you have orders and order details and products is child collection.

当用户想要按产品过滤时，我收到一个错误，因为没有属性或字段'PRODUCTS'存在于类型'ICollection 1'`

When user wants to filter by product I'm getting an error because of No property or field 'PRODUCTS' exists in type 'ICollection1'`

我写这样的查询。

var orders = _uow.Repository<ORDERS>()
    .Query()
    .Where("PRODUCTS.HEADING.ToLower().Contains(\"foo\")")
    .Include("ORDER_DETAILS")
    .Include("ORDER_DETAILS.PRODUCTS")
    .ToList();

因此，不可能像这样过滤子集合

So it's not possible to filter child collection like this? Or any way to filter?

感谢。

推荐答案

方式你命名你的类/属性，很难猜到哪一个是一个单一的对象，哪一个是一个集合属性。

From the way you named your classes/properties it's hard to guess which one is a single object and which one is a collection property.

如果 ORDERS class属性 ORDER_DETAILS ORDER_DETAILS 类和 ORDER_DETAILS 类属性产品 产品类的类的 HEADINGS ，那么下面应该做的技巧：

If ORDERS class property ORDER_DETAILS is a collection of ORDER_DETAILS class, and ORDER_DETAILS class property PRODUCTS is a singe object of PRODUCTS class having a string property HEADINGS, then the following should do the trick:

.Where("ORDER_DETAILS.Any(PRODUCTS.HEADING.ToLower().Contains(\"foo\"))")

基本上与使用lambda参数的静态查询相同

It's basically the same as static query with lambda parameters skipped

.Where(o => o.ORDER_DETAILS.Any(d => d.PRODUCTS.HEADING.ToLower().Contains("foo")))

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