使用LINQ，获取包含特定属性值的对象的列表

Question

I have two simple models:

 public class Product()
        {
           public long CategoryId {get; set;}
           //...etc
        }

 public class ProductCategory()
        {
           public long Id {get; set;}
           //...etc
        }

I've written a query to store a list of ProductCategory.Id numbers.

List<long> activeProductCategories

Now I would like to write a Linq Query that gets a List of all of the Products that have CategoryId equal to any long in activeProductCategories.

I have started writing something like the following, but have yet to make much progress:

List<Product> activeProducts = UnitOfWork.ProductRepository.Get().Where(a=>a.CategoryId //... ?

Answer 1

You can use a linq Contains() method

List<Product> activeProducts = UnitOfWork.ProductRepository.Get()
    .Where(a => activeProductCategories.Contains(a.CategoryId)).ToList();