c# - "OR"按需使用 Linq to Entities，我该怎么做？

Question

我有以下按需执行“AND”的查询:

var products = // Selecting a list of products in anywhere based in a filter...

foreach (var product in products)
{
    query = query.Where(p => p.Code == product.Code); // with this way, this query make no sense because this happens in any scenario, never a code can be more than one code.
}

那么，我怎样才能执行相同的查询但按需执行“或”(以便查询有意义)？

Answer 1

您可以将 IN 的传真用于 LINQ:

var productCodeList = products.Select(p => p.Code).ToList();

query = query.Where(p => productCodeList.Contains(p.Code));

基本上是说:

SELECT   *
FROM     products
WHERE    code IN (<list_of_codes>)