De/Serialize basic Linq Expressions using BinarySerializer

Question

I'm looking for a library/tool in order to be able to de/serialize Linq Expressions.

Is there some library over there? Is already suported natively on .Net? How could I get an starter stuff code?

Answer 1

It is unclear what you want to serialize: the result of a Linq expression, or the expression that you can use on a sequence.

IEnumerable<MyCollectionItem> MyCollection = ...;
IEnumerable<MyItem> result = MyCollection.LinqQuery(...);

Do you want to serialize result? or do you want to serialize LinqQuery, so you can use it later on a different collection:

IEnumerable<MyItem> otherResult = OtherCollection.DeserializedLinqQuery()

The first is easy: convert result to List<MyItem> and serialize / deserizalize the list.

The second is not really possible, after all, a LinqQuery is nothing more than a (possible composite) extension function to IEnumerable

static class MyCollectionItemExtensions
{
    public static IEnumerable<MyItem> MyLinqQuery(this IEnumerable<MyCollectionItem>(...)
    {
        ...
    }
 }

MyLinqQuery is a function, only after you've applied it to a sequence you get an object over which you can enumerate. It's not easy serialize a function.

However if MyLinqQuery is IQueryable, your query is not a function that is applied to elements of MyCollection, but something that has an expression that are applied to elements of MyCollection. You can ask the IQueryable for its expression and serialize that one.

There are several answers about how to do this in the article on StackOverflow: Serializing and deserialize expression tress