Managing Windows networks using Script - Part 12: Properties of the WMI class

Mitch Tulloch

Back in the third part of this series, we developed a simple script called displayTimeZone.vbs to display the current time zone setting on your computer:

Option Explicit
On Error Resume Next
Dim strComputer
Dim strWMINamespace
Dim strWMIQuery
Dim objWMIService
Dim colItems
Dim objItem

strComputer = "."
strWMINamespace = "rootCIMV2"
strWMIQuery = "SELECT * FROM Win32_TimeZone"

Set objWMIService = GetObject ("winmgmts:" & strComputer & strWMINamespace)
Set colItems = objWMIService.ExecQuery (strWMIQuery)

For Each objItem In colItems
WScript.Echo objItem.Caption
next

When I run this script, it gives the following result:

C: scripts>DisplayTimeZone.vbs
Microsoft (R) Windows Script Host Version 5.6
Copyright (C) Microsoft Corporation 1996-2001. All rights reserved.

(GMT-06: 00) Central Time (US & Canada)

How do I know that the main attribute of the Win32_TimeZone class includes the information I want to display? By reading the instructions about it here, I can know it. In fact, this MSDN page tells us that the Description property basically returns objItem.Description and similar results.

What else does this MSDN page tell us about the Win32_TimeZone class? What if I want to find out which month does it affect the computer? If you read through this page, you will get information related to this attribute (DaylightMonth).

DaylightMonth
Data type: uint32
Access type: Read-only

Value Meaning
first
0x1 January
2
0x2 February
3
0x3 March
4
0x4 April
5
0x5 Sewing
6
0x6 June
7
0x7 July
8
0x8 August
9
0x9 September
ten
0xA October
11
0xB November
twelfth
0xC December

To use this information, I simply change the WScript.Echo objItem.Caption line to WScript.Echo objItem.DaylightMonth and this is what I get when running this script:

C: scripts>DisplayTimeZone.vbs
Microsoft (R) Windows Script Host Version 5.6
Copyright (C) Microsoft Corporation 1996-2001. All rights reserved.

3

List the properties of a class

Now we can continue the process by changing the properties in WScript.Echo objItem. And so slowly work through displaying each one of the properties of the Win32_TimeZone class, but is this an easier way? Can we display the properties of this class in a script without naming them in the script? This is done but before doing so try and list the number of attributes of this class. This is how we do it:

Option Explicit
On Error Resume Next
Dim strComputer
Dim strWMINamespace
Dim strWMIQuery
Dim objWMIService
Dim colItems
Dim objItem

strComputer = "."
strWMINamespace = "rootCIMV2"
strWMIQuery = ": Win32_TimeZone"

Set objWMIService = GetObject ("winmgmts:" & strComputer & strWMINamespace & strWMIQuery)
WScript.Echo "Number of properties of" & strWMIQuery & "class is" & objWMIService.Properties_.count

Here is the result of running this new script, the script we will call it DisplayClassProperties.vbs :

C: scripts>DisplayClassProperties.vbs
Microsoft (R) Windows Script Host Version 5.6
Copyright (C) Microsoft Corporation 1996-2001. All rights reserved.

Number of properties of: Win32_TimeZone class is 24

Viewing an inventory of properties at Win32_TimeZone MSDN will show us that the number 24 is completely correct, which means that the Win32_TimeZone class has 24 properties in total.

How does this new scenario work? First, note that instead of connecting to the default namespace ("rootCIMV2") on the local computer ('.') We connect directly to the Win32_TimeZone class on the computer. In other words, the line:

Set objWMIService = GetObject ("winmgmts:" & strComputer & strWMINamespace & strWMIQuery)

can be replaced by

Set objWMIService = GetObject ("winmgmts: .rootCIMV2: Win32_TimeZone")

and it will perform the work in a similar way. Another thing you will notice is one in the last line of the script:

objWMIService.Properties_.count

We know about attributes (like)

Indeed SWbemObject.Properties_ is a collection (a type of object) and when the object has properties, you can use these properties. An attribute that a collection has is .count, it can return the number of properties of the object, ie . returns the number of elements in the collection. This means that SWbemObject.Properties_.count is a .count property of the SWbemObject.Properties_ object, so there are two cycles instead of a regular cycle in the syntax.

Show properties of the class

Now we can list the properties of the Win32_TimeZone class, how can we return the names of the properties? By appending the following lines to the end of the DisplayClassProperties.vbs script:

For Each objItem in objWMIService.Properties_
Wscript.Echo "Property:" & objItem.name
next

This is what we have when running the script:

C: scripts> DisplayClassProperties.vbs
Microsoft (R) Windows Script Host Version 5.6
Copyright (C) Microsoft Corporation 1996-2001. All rights reserved.

Number of properties of: Win32_TimeZone class is 24
Property: Bias
Property: Caption
Property: DaylightBias
Property: DaylightDay
Property: DaylightDayOfWeek
Property: DaylightHour
Property: DaylightMillisecond
Property: DaylightMinute
Property: DaylightMonth
Property: DaylightName
Property: DaylightSecond
Property: DaylightYear
Property: Description
Property: SettingID
Property: StandardBias
Property: StandardDay
Property: StandardDayOfWeek
Property: StandardHour
Property: StandardMillisecond
Property: StandardMinute
Property: StandardMonth
Property: StandardName
Property: StandardSecond
Property: StandardYear

Checking out the previous MSDN page, the page described about the Win32_TimeZone class, we can see above that the name of the class properties.

Conclude

The power of this method is that it allows us to list the properties of the WMI class, so we can learn more about them (remember that in Part 3 of this series we saw how to list the WMI layer of a namespace and together with that list we can discover and see what we can manage through using WMI).

For example, if we want to list the properties of the Win32_BootConfiguration WMI class using the DisplayClassProperties.vbs script, all we need to do is change the line:

strWMIQuery = ": Win32_TimeZone"

into the following line:

strWMIQuery = ": Win32_BootConfiguration"

When we make this change and re-run the script, we get the result:

C: scripts> DisplayClassProperties.vbs
Microsoft (R) Windows Script Host Version 5.6
Copyright (C) Microsoft Corporation 1996-2001. All rights reserved.

Number of properties of: Win32_BootConfiguration class is 9
Property: BootDirectory
Property: Caption
Property: ConfigurationPath
Property: Description
Property: LastDrive
Property: Name Value:
Property: ScratchDirectory
Property: SettingID
Property: TempDirectory

We recommend that you use this article section along with the third part to exploit the WMI class and their other attributes, plus we can see more details about the power of using WMI to manage machines. Calculate Windows in later articles of this series, invite you to read.

David Pac

Update 26 May 2019