Win32_DeviceChangeEvent - powershell.one

The Win32_DeviceChangeEvent abstract WMI class represents device change events that result from the addition, removal, or modification of devices on the computer system. This includes changes in the hardware configuration (docking and undocking), the hardware state, or newly mapped devices (mapping of a network drive). For example, a device has changed when a WM_DEVICECHANGE message is sent.

Methods

Win32_DeviceChangeEvent has no methods.

Properties

Win32_DeviceChangeEvent returns 3 properties:

'EventType','SECURITY_DESCRIPTOR','TIME_CREATED'

Unless explicitly marked as writeable, all properties are read-only. Read all properties for all instances:

Get-CimInstance -ClassName Win32_DeviceChangeEvent -Property *

Most WMI classes return one or more instances.

When Get-CimInstance returns no result, then apparently no instances of class Win32_DeviceChangeEvent exist. This is normal behavior.

Either the class is not implemented on your system (may be deprecated or due to missing drivers, i.e. CIM_VideoControllerResolution), or there are simply no physical representations of this class currently available (i.e. Win32_TapeDrive).

EventType

UINT16

Type of event change notification that has occurred.

EventType returns a numeric value. To translate it into a meaningful text, use any of the following approaches:

Use a PowerShell Hashtable

$EventType_map = @{
      1 = 'Configuration Changed'
      2 = 'Device Arrival'
      3 = 'Device Removal'
      4 = 'Docking'
}

Use a switch statement

switch([int]$value)
{
  1          {'Configuration Changed'}
  2          {'Device Arrival'}
  3          {'Device Removal'}
  4          {'Docking'}
  default    {"$value"}
}

Use Enum structure

Enum EnumEventType
{
  Configuration_Changed   = 1
  Device_Arrival          = 2
  Device_Removal          = 3
  Docking                 = 4
}

Examples

Use $EventType_map in a calculated property for Select-Object

<# 
  this example uses a hashtable to translate raw numeric values for 
  property "EventType" to friendly text

  Note: to use other properties than "EventType", look up the appropriate 
  translation hashtable for the property you would like to use instead.
#>

#region define hashtable to translate raw values to friendly text

# Please note: this hashtable is specific for property "EventType" 
# to translate other properties, use their translation table instead
$EventType_map = @{
      1 = 'Configuration Changed'
      2 = 'Device Arrival'
      3 = 'Device Removal'
      4 = 'Docking'
}

#endregion define hashtable

#region define calculated property (to be used with Select-Object)

<#
  a calculated property is defined by a hashtable with keys "Name" and "Expression"
  "Name" defines the name of the property (in this example, it is "EventType", but you can rename it to anything else)
  "Expression" defines a scriptblock that calculates the content of this property
  in this example, the scriptblock uses the hashtable defined earlier to translate each numeric
  value to its friendly text counterpart:
#>
 
$EventType = @{
  Name = 'EventType'
  Expression = {
    # property is an array, so process all values
    $value = $_.EventType
    $EventType_map[[int]$value]
  }  
}
#endregion define calculated property

# retrieve the instances, and output the properties "Caption" and "EventType". The latter
# is defined by the hashtable in $EventType: 
Get-CimInstance -Class Win32_DeviceChangeEvent | Select-Object -Property Caption, $EventType

# ...or dump content of property EventType:
$friendlyValues = Get-CimInstance -Class Win32_DeviceChangeEvent | 
    Select-Object -Property $EventType |
    Select-Object -ExpandProperty EventType

# output values
$friendlyValues

# output values as comma separated list
$friendlyValues -join ', '

# output values as bullet list
$friendlyValues | ForEach-Object { "- $_" }

Use $EventType_map to directly translate raw values from an instance

<# 
  this example uses a hashtable to manually translate raw numeric values 
  for property "Win32_DeviceChangeEvent" to friendly text. This approach is ideal when
  there is just one instance to work with.

  Note: to use other properties than "Win32_DeviceChangeEvent", look up the appropriate 
  translation hashtable for the property you would like to use instead.
#>

#region define hashtable to translate raw values to friendly text

# Please note: this hashtable is specific for property "Win32_DeviceChangeEvent" 
# to translate other properties, use their translation table instead
$EventType_map = @{
      1 = 'Configuration Changed'
      2 = 'Device Arrival'
      3 = 'Device Removal'
      4 = 'Docking'
}

#endregion define hashtable

# get one instance:
$instance = Get-CimInstance -Class Win32_DeviceChangeEvent | Select-Object -First 1

<#
  IMPORTANT: this example processes only one instance to illustrate
  the number-to-text translation. To process all instances, replace
  "Select-Object -First 1" with a "Foreach-Object" loop, and use
  the iterator variable $_ instead of $instance
#>

# query the property
$rawValue = $instance.EventType  

# translate raw value to friendly text:
$friendlyName = $EventType_map[[int]$rawValue]

# output value
$friendlyName

Use a switch statement inside a calculated property for Select-Object

<# 
  this example uses a switch clause to translate raw numeric 
  values for property "EventType" to friendly text. The switch
  clause is embedded into a calculated property so there is
  no need to refer to external variables for translation.

  Note: to use other properties than "EventType", look up the appropriate 
  translation switch clause for the property you would like to use instead.
#>

#region define calculated property (to be used with Select-Object)

<#
  a calculated property is defined by a hashtable with keys "Name" and "Expression"
  "Name" defines the name of the property (in this example, it is "EventType", but you can rename it to anything else)
  "Expression" defines a scriptblock that calculates the content of this property
  in this example, the scriptblock uses the hashtable defined earlier to translate each numeric
  value to its friendly text counterpart:
#>
 
$EventType = @{
  Name = 'EventType'
  Expression = {
    # property is an array, so process all values
    $value = $_.EventType
    
    switch([int]$value)
      {
        1          {'Configuration Changed'}
        2          {'Device Arrival'}
        3          {'Device Removal'}
        4          {'Docking'}
        default    {"$value"}
      }
      
  }  
}
#endregion define calculated property

# retrieve all instances...
Get-CimInstance -ClassName Win32_DeviceChangeEvent | 
  # ...and output properties "Caption" and "EventType". The latter is defined
  # by the hashtable in $EventType:
  Select-Object -Property Caption, $EventType

Use the Enum from above to auto-translate the code values

<# 
  this example translates raw values by means of type conversion
  the friendly names are defined as enumeration using the
  keyword "enum" (PowerShell 5 or better)
  
  The raw value(s) are translated to friendly text by 
  simply converting them into the enum type.
  
  Note: to use other properties than "Win32_DeviceChangeEvent", look up the appropriate 
  enum definition for the property you would like to use instead.
#>


#region define enum with value-to-text translation:
Enum EnumEventType
{
  Configuration_Changed   = 1
  Device_Arrival          = 2
  Device_Removal          = 3
  Docking                 = 4
}

#endregion define enum

# get one instance:
$instance = Get-CimInstance -Class Win32_DeviceChangeEvent | Select-Object -First 1

<#
  IMPORTANT: this example processes only one instance to focus on
  the number-to-text type conversion. 
  
  To process all instances, replace   "Select-Object -First 1" 
  with a "Foreach-Object" loop, and use the iterator variable 
  $_ instead of $instance
#>

# query the property:
$rawValue = $instance.EventType

#region using strict type conversion

<#
  Note: strict type conversion fails if the raw value is 
  not defined by the enum. So if the list of allowable values
  was extended and the enum does not match the value,
  an exception is thrown
#>

# convert the property to the enum **EventType** 
[EnumEventType]$rawValue 

# get a comma-separated string:
[EnumEventType]$rawValue -join ',' 
#endregion

#region using operator "-as"

<#
  Note: the operator "-as" accepts values not defined
  by the enum and returns $null instead of throwing
  an exception
#>

$rawValue -as [EnumEventType]
#endregion

Enums must cover all possible values. If EventType returns a value that is not defined in the enum, an exception occurs. The exception reports the value that was missing in the enum. To fix, add the missing value to the enum.

SECURITY_DESCRIPTOR

UINT8 ARRAY

Get-CimInstance -ClassName Win32_DeviceChangeEvent | Select-Object -Property SECURITY_DESCRIPTOR

TIME_CREATED

UINT64

Unique value that indicates the time at which the event was generated. This is a 64-bit value that represents the number of 100-nanosecond intervals after January 1, 1601. The information is in the Coordinated Universal Times (UTC) format.

For more information about using uint64 values in scripts, see Scripting in WMI.

Get-CimInstance -ClassName Win32_DeviceChangeEvent | Select-Object -Property TIME_CREATED

Examples

List all instances of Win32_DeviceChangeEvent

Get-CimInstance -ClassName Win32_DeviceChangeEvent

Learn more about Get-CimInstance and the deprecated Get-WmiObject.

View all properties

Get-CimInstance -ClassName Win32_DeviceChangeEvent -Property *

View key properties only

Get-CimInstance -ClassName Win32_DeviceChangeEvent -KeyOnly

Selecting Properties

To select only some properties, pipe the results to Select-Object -Property a,b,c with a comma-separated list of the properties you require. Wildcards are permitted.

Get-CimInstance always returns all properties but only retrieves the ones that you specify. All other properties are empty but still present. That’s why you need to pipe the results into Select-Object if you want to limit the visible properties, i.e. for reporting.

Selecting Properties

The code below lists all available properties. Remove the ones you do not need:

$properties = 'EventType',
              'SECURITY_DESCRIPTOR',
              'TIME_CREATED'
Get-CimInstance -ClassName Win32_DeviceChangeEvent | Select-Object -Property $properties

Limiting Network Bandwidth

If you work remotely, it makes sense to limit network bandwidth by filtering the properties on the server side, too:

Get-CimInstance -Class Win32_DeviceChangeEvent -Property $property | 
Select-Object -Property $property

Selecting Instances

To select some instances, use Get-CimInstance and a WMI Query. The wildcard character in WMI Queries is % (and not “*”).

The parameter -Filter runs a simple query.

Listing all instances where the property Caption starts with “A”

Get-CimInstance -Class Win32_DeviceChangeEvent -Filter 'Caption LIKE "a%"' 

Using a WQL Query

The parameter -Query uses a query similar to SQL and combines the parameters -Filter and -Property. This returns all instances where the property Caption starts with “A”, and returns the properties specified:

Get-CimInstance -Query "SELECT SECURITY_DESCRIPTOR, TIME_CREATED, EventType FROM Win32_DeviceChangeEvent WHERE Caption LIKE 'a%'"

Any property you did not specify is still present but empty. You might need to use Select-Object to remove all unwanted properties:
Get-CimInstance -Query "SELECT SECURITY_DESCRIPTOR, TIME_CREATED, EventType FROM Win32_DeviceChangeEvent WHERE Caption LIKE 'a%'" | Select-Object -Property SECURITY_DESCRIPTOR, TIME_CREATED, EventType

Accessing Remote Computers

To access remote systems, you need to have proper permissions. User the parameter -ComputerName to access one or more remote systems.

Authenticating as Current User

# one or more computer names or IP addresses:
$list = 'server1', 'server2'

# authenticate with your current identity:
$result = Get-CimInstance -ClassName Win32_DeviceChangeEvent -ComputerName $list 
$result

Authenticating as Different User

Use a CIMSession object to authenticate with a new identity:

# one or more computer names or IP addresses:
$list = 'server1', 'server2'

# authenticate with a different identity:
$cred = Get-Credential -Message 'Authenticate to retrieve WMI information:'
$session = New-CimSession -ComputerName $list -Credential $cred

$result = Get-CimInstance Win32_DeviceChangeEvent -CimSession $session

# remove the session after use (if you do not plan to re-use it later)
Remove-CimSession -CimSession $session

$result

Learn more about accessing remote computers.

Requirements

To use Win32_DeviceChangeEvent, the following requirements apply:

PowerShell

Get-CimInstance was introduced with PowerShell Version 3.0, which in turn was introduced on clients with Windows 8 and on servers with Windows Server 2012.

If necessary, update Windows PowerShell to Windows PowerShell 5.1, or install PowerShell 7 side-by-side.

Operating System

Win32_DeviceChangeEvent was introduced on clients with Windows Vista and on servers with Windows Server 2008.

Namespace

Win32_DeviceChangeEvent lives in the Namespace Root/CIMV2. This is the default namespace. There is no need to use the -Namespace parameter in Get-CimInstance.

Implementation

Win32_DeviceChangeEvent is implemented in CIMWin32.dll and defined in CIMWin32.mof. Both files are located in the folder C:\Windows\system32\wbem:

explorer $env:windir\system32\wbem
notepad $env:windir\system32\wbem\CIMWin32.mof

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