Author Posts

October 28, 2016 at 2:18 pm

Hi,
Any idea why this is happening ?
On a windows 10

PS C:\> $os = Get-WmiObject win32_operatingsystem
PS C:\> $o.version -gt 6.2
False

While in Win 8.1

PS C:\> $os = Get-WmiObject win32_operatingsystem
PS C:\> $o.version -gt 6.2
True

October 28, 2016 at 2:21 pm

See the documentation at https://msdn.microsoft.com/en-us/library/aa394239(v=vs.85).aspx.

Version is a string; you can't do numeric comparisons with it, unless you cast it as a [single] first. And even that will fail if the version is ever something like 6.2.2, since that's not actually a number.

October 28, 2016 at 2:25 pm

Wouldn't it work when you cast it to [VERSION]?

October 28, 2016 at 2:26 pm

You'd have to cast both values – the Version property and the 6.2 comparison – to [version], but yes, that's what [version] is for.

October 28, 2016 at 4:09 pm

Cool ... thanks

October 28, 2016 at 4:49 pm

The casting that is being referred to would be something like this:

[version]$os.Version -gt [version]"6.2"

Powershell will do type conversions for you in some cases, however, "strong-typed" code will not leave things to chance. You want to do comparisons to the same type string to string, int to int, etc. and in this case version to version. Casting attempts to convert the value to the type so that a proper comparison can be done. Even when I was playing with the version cast, it didn't like X.0:

PS C:\Users\Rob> [version]10.0
Cannot convert value "10" to type "System.Version". Error: "Version string portion was too short or too long."
At line:1 char:1
+ [version]10.0
+ ~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvalidCastParseTargetInvocation
 

PS C:\Users\Rob> [version]"10.0"

Major  Minor  Build  Revision
-----  -----  -----  --------
10     0      -1     -1      

It's especially important when doing comparisons like -gt, because you are basically doing something like TEN -gt 6.2.

October 31, 2016 at 7:43 am

exactly what i was looking for , the [version] cast , didn't know about it before
nice find 🙂

PS C:\> [version]$os.version -gt [version]"6.2"
True