Vista - meaning of this cast ?

About this line:

$wmi = [wmiclass]"\\.\ROOT\CIMV2:Win32_Service"

could someone explain to me the meaning of this? I know that it creates an
instance of wmiclass, but what PS language feature is in use?

Thanks,

Leo

Hi Leo

Check out the Windows PowerShell team blog, you'll find there various techniques
to get WMI objects and classes.

Improved Support for WMI
http://blogs.msdn.com/powershell/arc...26/647038.aspx


-----
Shay Levi
$cript Fanatic
http://scriptolog.blogspot.com

first to type cast something in powershell you use the typename like this

[double]2

will return a double rather than just an integer.. however if also is
more than just typecasting you can convert such as

[int]"2"

basically the powershell engine will do whatever it can to try to
convert the object into the type specified.. but it goes ever further

certian classes have an ADAPTER, where the adapter has methods to try to
convert things into the object..

i.e
[xml] actually returns a dotnet xmldocument object..
so the adapter allows you to do a few things.. one is convert a string
into an xmldocument

$a = [xml] "<parent><child>something</child></parent>"

additionaly the adapter does other things, in the XML case.. an
XMldocument dotnet object has a set of static methods and properties,
however the adapter in powershell allows you to do

$a.parent.child

which of course is contextual to the contents of the xmldocument.. which
is really cool.

so in your case the wmiclass adapter converts a valid WMI path/query and
returns a dotnet system.management.managementobject .. the [ADSI]
adapter does likewise the an ldap path/query

alternatively you could have used the get-wmiobject cmdlet to do the
same thing

get-WmiObject win32_service -namespace "root/cimv2"

but the great thing about the adapter is you have alot of those WMI
strings hanging around in previous vbscripts or on the internet etc.

also the adapter in wmi is doing other great things, grabbing the
properties on each specific WMI class, and adapting to to the wmi
management object..

i.e

gwmi win32_service |Select-Object *
gwmi win32_process |Select-Object *

and you'll notice different properties specific to a service or a
process, even though the resulting object type is
system.management.managementobject each time.





Leo Tohill wrote:

very cool. Thanks.

"Karl Prosser[MVP]" wrote: