OData - 在$ expand中对集合进行嵌套$过滤

Question

Similar to this example I'd like to filter a collection in "Order". http://odata.github.io/WebApi/04-03-filter-in-expand/

Let's say we have following model:

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Order> Orders { get; set; }
}

public class Order
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Article> Articles { get; set; }
}

public class Article
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Category { get; set; }
}

If I call following URI .../Customers?$expand=Orders($filter=Articles/Category eq 'Cookies') , I get an error saying

The parent value for a property access of a property 'Category' is not a single value. Property access can only be applied to a single value.

But I can use a construct like: .../Customers?$expand=Orders($filter=Articles/any(a:a/Category eq 'Cookies'))

The problem with any or all is, that it is filtering the parant data, based on the children. Af "articles" with the "Category" are existing, it will return all articles. But I want to reduce the child-items to show only the articles of category "cookie".

Answer 1

I think you need to use two nested different any , if I understand you, you want to filter all the Articles they are in Cookies category, I think you need something like :

.../Customers?$filter= Orders/any(o: o/Articles/any(p: p/Category eq 'Cookies'))

it will give you all Customers which have Orders if Orders have cookies Articles .

Regards.