实体框架 - 获取记录：逗号分隔的字符串（或 List<string>）包含在实体集合中

Question

给定实体

public class Product
{
    public int ProductId { get; set; }
    public string ProductName { get; set; }
    public ICollection<Category> Categories { get; set; }
}

public class Category
{
    public int CategoryId { get; set; }
    public string CategoryName { get; set; }
    public ICollection<Product> Products { get; set; }
}

我想查询 Products 表以检索具有以逗号分隔列表形式给出的任何类别的产品。

因此，例如，我想获得类别为“电子产品”和/或“厨房设备”的产品

如果它不是一个集合，我会这样做：例如

Products.Where(p => "Oven,Kettle".Contains(p.ProductName));

但这显然行不通：

Products.Where(p => "Electronics,Kitchen Equipment".Contains(p.Categories.CategoryName));

也试过了：

Products.Where(p => "Electronics,Kitchen Equipment".Any(x => p.Categories.Any(pcat => pcat.CategoryName == x.ToString()))).Take(100);

Answer 1

您必须将 IEnumerable 传递给 Where 子句：

var names = "Oven,Kettle".Split(',');
var query = Products.Where(p => names.Contains(p.ProductName));

Answer 2

var categories = new[] { "Electronics", "Kitchen Equipment" };

var productsQuery = Products
    .Where(p => p.Categories.Any(pcat => categories.Contains(pcat.CategoryName)))
    .Take(100);