Extract information from Func <bool, T> or similar lambda

Question

I am trying to create a general cache level. ICacheRepository

Say I have the following:

public class Person
{
    public int PersonId { get; set; }
    public string Firstname { get; set; }
    public string Lastname { get; set; }
    public DateTime Added { get; set; }
}

And I have something like this:

list.Where(x => x.Firstname == "Syska");

Here I want to extract the above information in order to check if the "PersonId" query has provided, which it does not have, so I do not want to cache it.

But I will say that I run this request:

list.Where(x => x.PersonId == 10);

Since PersonId is my key ... I want to cache it. with a key like "Person_10", and later I can extract it from the cache.

I know that you can extract information using Expression<Func<>>, but there seems to be a lot of overhead for this (when starting compilation and extracting Constant values, etc. and a bunch of cache to make sure the analysis is correct)

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EF Code First CTP5.

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repository.SingleOrDefault(x => x.Email == "[e-mail]");

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Expression<Func<User, bool>> b;
b.Body // Here I can extract most information without compiling it, to fetch what its being quried for.

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BinaryExpression.... . .

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Answer 1

, Expression<Func<bool, T>>. ( ), , . , ORM, LINQ-to-SQL Entity Framework, (LINQ-to-SQL SQL, Entity Framework EntitySQL ..).

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• IQueryable<T>. , LINQ ( ).
• Where , Expression<Func<bool, T>>.

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Answer 2

Person GetById(this List<Person> list, int personId). , , , .