Cast an object to an array of string?

Question

I have this code:

Strutture = from Ricettivito s in Strutture
            where s.ServiziAttivi.Cast<string>().Intersect(IDSServizi).Count() == IDSServizi.Count()
            select s;

I need to:

Cast ServiziAttivi (which is a list of MyService) into a list of string (which must contains MyService.UniqueID)
Than, check if this list contains each elements of IDSServizi (which is a list of string).

But seems I cannot doint that conversion?

Only you can tell us why you can't do that conversion - what's the error message? — J. Steen, Apr 17 '13 at 14:20
`Unable to cast object of type 'Ricettivita.MyService' to type 'System.String'.` — markzzz, Apr 17 '13 at 14:20
I need to extract `Ricettivito` which `ServiziAttivi` that contains each values inside IDSServizi — markzzz, Apr 17 '13 at 14:22
Rather than casting, try `.Select`-ing the `UniqueID` from the `ServiziAttivi`-list. — J. Steen, Apr 17 '13 at 14:22
Check this thread. http://stackoverflow.com/questions/1407689/how-do-i-provide-custom-cast-support-for-my-class — , Apr 17 '13 at 14:30

score 4 · Accepted Answer · answered Apr 17 '13 at 14:27

4

First cast to .Cast<Ricettivita.MyService>() then select a string property.

    where s.ServiziAttivi
             .Cast<Ricettivita.MyService>()
             .Select(x=>x.UniqueID).Intersect(IDSServizi).Count()

answered Apr 17 '13 at 14:27

I4V

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If OP did a .ToList() would they need a cast, first? Assuming OPs custom collection class inherits from Enumerable in some way. – J. Steen Apr 17 '13 at 14:30

score 1 · Answer 2 · answered Apr 17 '13 at 14:22

1

I think you should use Select instead of Cast:

Strutture = from Ricettivito s in Strutture
            where s.ServiziAttivi.Select(x => (string)x.UniqueID).Intersect(IDSServizi).Count() == IDSServizi.Count()
            select s;

answered Apr 17 '13 at 14:22

MarcinJuraszek

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I can't. Check the answer to @Michael Perrenoud – markzzz Apr 17 '13 at 14:24

Cast an object to an array of string?

2 Answers2