Linq, and how to determine if IEnumerable<T>

[GiJeet]

Hello, I know that all that’s required to use linq to objects, is the
collection must implement IEnumerable<Tbu t how to know if a
collection implements this interface? For example one of the books
I’m reading uses the running system processes and I wouldn't know off
the top of my head if these processes implement the IEnumerable<T>
interface so is there a quick way to know if some objects implement
this interface without writing code to test it?

thx
G

[Jon Skeet [C# MVP]]

GiJeet <gi****@yahoo.c omwrote:

Hello, I know that all that=3Fs required to use linq to objects, is the
collection must implement IEnumerable<Tbu t how to know if a
collection implements this interface? For example one of the books
I=3Fm reading uses the running system processes and I wouldn't know off
the top of my head if these processes implement the IEnumerable<T>
interface so is there a quick way to know if some objects implement
this interface without writing code to test it?

Pretty much every collection implements at least IEnumerable. For any
particular collection though, just check the documentation.

I wouldn't expect a single process to implement IEnumerable<T>, but the
*collection* of running processes almost certainly will.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

[GiJeet]

but the *collection* of running processes almost certainly will.

So, just to make sure I have this correct, it’s always the collection
we create to hold our objects, whether we create a List<Tor Array or
Collection<Tor even IEnumerable<Tth at needs to implement this
interface and it doesn’t matter what objects we insert into the
collect (system processes, strings, ints, cars, etc), because it’s the
collect we enumerate over. Do I have this right?

G

[GiJeet]

On Apr 26, 5:47 pm, GiJeet <gij...@yahoo.c omwrote:

but the *collection* of running processes almost certainly will.

Are we always querying against a collection (in Linq-to-objects)? I
hear the term "queryable types", is this referring to just collections
or ANY object that implements IEnumerable? So, I guess I'm still not
clear on exactly what we can query against...objec ts? collections?
both?

G

[Jon Skeet [C# MVP]]

GiJeet <gi****@yahoo.c omwrote:

but the *collection* of running processes almost certainly will.

So, just to make sure I have this correct, it=3Fs always the collection
we create to hold our objects, whether we create a List<Tor Array or
Collection<Tor even IEnumerable<Tth at needs to implement this
interface and it doesn=3Ft matter what objects we insert into the
collect (system processes, strings, ints, cars, etc), because it=3Fs the
collect we enumerate over. Do I have this right?

Yes.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

[Jon Skeet [C# MVP]]

GiJeet <gi****@yahoo.c omwrote:

On Apr 26, 5:47 pm, GiJeet <gij...@yahoo.c omwrote:

but the *collection* of running processes almost certainly will.

Are we always querying against a collection (in Linq-to-objects)?

Well, querying against "something that implements IEnumerable".
(Usually IEnumerable<Tas well.) It doesn't need to be an in-memory
collection, for example.

I hear the term "queryable types", is this referring to just collections
or ANY object that implements IEnumerable? So, I guess I'm still not
clear on exactly what we can query against...objec ts? collections?
both?

Anything that implements IEnumerable/IEnumerable<T>. (Most of LINQ to
Objects requires IEnumerable<T>, but you can use Cast/OfType to obtain
an IEnumerable<Tfr om an IEnumerable.)

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk