Strange problem with select-string

Question

Hello
i wonder why the first command delivers desired output but the second doesn't. is there any technical explanation for this issue?
1st command:
PS C:\>IPConfig | Select-String -Pattern 'IPV4'
output:  IPv4 Address. . . . . . . . . . . : 10.1.1.1
2nd set of commands:
# none of the following commands generates output !!!!
(Get-WmiObject Win32_OperatingSystem) | Select-String -Pattern 'version'
#or
Get-WmiObject Win32_OperatingSystem | Select-String -Pattern 'version'
#or
[string]$var = Get-WmiObject win32_operatingSystem
$var | Select-String -Pattern 'version'
#or
[Array]$var = Get-WmiObject win32_operatingSystem
$var | Select-String -Pattern 'version'
what can be the reason?
( i do know that there are lots of workarounds to achieve that, for example redirecting Get-WmiObject win32_operatingSystem to a text file & the Get-content that text file piped into select string. but i need to know the reason about above examples since
the mechanism is the same !)
thanks in advanced

Answer 1

Hi,
You have an object, not a string.H
(Get-WmiObject Win32_OperatingSystem).Version should give you what you're looking for.
Some examples:
PS C:\> $ipconfig = ipconfig
PS C:\> $ipconfig.GetType()
IsPublic IsSerial Name BaseType
True True Object[] System.Array
PS C:\> $ipconfig[0].GetType()
IsPublic IsSerial Name BaseType
True True String System.Object
PS C:\> $os = Get-WmiObject Win32_OperatingSystem
PS C:\> $os.GetType()
IsPublic IsSerial Name BaseType
True True ManagementObject System.Management.ManagementBaseObject
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Hi Mike, thanks a lot for Great explanation.
so i tried to convert the result of Get-WmiObject Win32_OperatingSystem as string or Array. but still no effect:
$a = Get-WmiObject Win32_OperatingSystem
$a.GetType() | ft name,fullname -AutoSize
<# result is :
# Name FullName
ManagementObject System.Management.ManagementObject
#>
$b = $a.ToString()
$b.GetType()
# output IsPublic IsSerial Name BaseType
#True True String System.Object
$b | Select-String -Pattern 'version'
# no result
Select-String -Pattern 'version' -InputObject $b
# result is: \\WIN8-NOTEBOOK\root\cimv2:Win32_OperatingSystem=@
# now trying to make output be Array:
$c = @(Get-WmiObject Win32_OperatingSystem)
$c | Select-String -Pattern 'version'
# no result
Select-String -Pattern 'version' -InputObject $c
# no result
any more help ?