如何筛选子集合使用LINQ动态

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。

答

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")))

如何筛选子集合使用LINQ动态

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