Question

I am using PowerShell 2.0 and trying to get the possible methods from Win32_ShadowCopy.

Now, when I use Get-WmiObject -list Win32_ShadowCopy | Get-Member I get:

   TypeName: System.Management.ManagementClass#ROOT\cimv2\Win32_ShadowCopy

Name                MemberType    Definition
----                ----------    ----------
Name                AliasProperty Name = __Class
Create              Method        System.Management.ManagementBaseObject Cre...
...

But if I use Get-WmiObject Win32_ShadowCopy | Get-Member i get:

   TypeName: System.Management.ManagementObject#root\cimv2\Win32_ShadowCopy

Name                MemberType   Definition
----                ----------   ----------
Revert              Method       System.Management.ManagementBaseObject Reve...
Caption             Property     System.String Caption {get;set;}
...

Now I don’t understand. Why do I get 2 seemingly different classes? I expect the same result with both commands. I can find what -list does in the documentation, but not what the default behavior is without the -list switch. Anyone care to clarify?

Answer 1

This is from get-help about list.

-List []
Specifies whether to retrieve and display the names of the WMI classes
in the WMI repository namespace that is specified in the Namespace para
meter. The Default Namespace registry entry in the HKEY_LOCAL_MACHINE\
SOFTWARE\Microsoft\WBEM\Scripting registry key is not used by this cmdl
et to determine the default namespace. If you specify the List paramete
r but not the Namespace parameter, the root\CIMV2 namespace is used by
default.

Required?                    false
Position?                    named
Default value
Accept pipeline input?       false
Accept wildcard characters?  false

for your script

Get-WmiObject -list Win32_ShadowCopy

equals:

Get-WmiObject -list -class Win32_ShadowCopy

which means you’re listing classes with name Win32_ShadowCopy.

And the

Get-WmiObject Win32_ShadowCopy

equals:

Get-WmiObject -Class Win32_ShadowCopy

which returns the objects of the specified class.