Get Screen resolution using WMI/powershell in Windows 7

I am using the following script to get screen resolution in Windows using WMI. The script works fine when the computer is in landscape mode but returns incorrect values when in portrait mode. Works properly in XP and did not try in Vista. Can anyone confirm this is bug in Windows 7 WMI.

strComputer = "." 
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\CIMV2") 
Set colItems = objWMIService.ExecQuery( _
    "SELECT * FROM Win32_DesktopMonitor",,48) 
For Each objItem in colItems 
    Wscript.Echo "-----------------------------------"
    Wscript.Echo "Win32_DesktopMonitor instance"
    Wscript.Echo "-----------------------------------"
    Wscript.Echo "ScreenHeight: " & objItem.ScreenHeight
    Wscript.Echo "ScreenWidth: " & objItem.ScreenWidth
Next

For the record, the PowerShell code is:

Get-WmiObject -Class Win32_DesktopMonitor | Select-Object ScreenWidth,ScreenHeight

I get the same values in Landscape or in Portrait mode.

UPDATE:

In a multi monitor environment you can get the info for all monitors with:

PS> Add-Type -AssemblyName System.Windows.Forms
PS> [System.Windows.Forms.Screen]::AllScreens


BitsPerPixel : 32
Bounds       : {X=0,Y=0,Width=1280,Height=800}
DeviceName   : \\.\DISPLAY1
Primary      : True
WorkingArea  : {X=0,Y=0,Width=1280,Height=770}

BitsPerPixel : 32
Bounds       : {X=1280,Y=0,Width=1920,Height=1200}
DeviceName   : \\.\DISPLAY2
Primary      : False
WorkingArea  : {X=1280,Y=0,Width=1920,Height=1170}

You can grab this from the Win32_VideoController WMI class. The VideoModeDescription property includes the screen resolution and the color depth.

(Get-WmiObject -Class Win32_VideoController).VideoModeDescription;

Result

1600 x 900 x 4294967296 colors