Powershell how to find the property type of a registry item property-CodePudding

I've found several examples showing how to get, set, and create registry keys as well as their properties and values. I need to find what property type a registry key property has (DWord, String, Multistring etc.)

If I do Get-ItemProperty I can fetch the values of a property, like so:

PS C:\> Get-ItemProperty "HKLM:\SOFTWARE\MySoftware\MyKey\" -Name MyProperty


MyProperty    : MyValue
PSPath        : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\MySoftware\MyKey\
PSParentPath  : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\MySoftware
PSChildName   : MyValue
PSDrive       : HKLM
PSProvider    : Microsoft.PowerShell.Core\Registry

However, this does not tell me if the value of MyProperty is a string, a DWord, a multistring, or whatever else it might be. The only way I've found to get that information is to pipe it to Get-Member, because the Definition tells me what type it is:

PS C:\> Get-ItemProperty "HKLM:\SOFTWARE\MySoftware\MyKey\" -Name MyProperty | Get-Member
                                                                                                                                                                                                                                                                 

TypeName: System.Management.Automation.PSCustomObject

Name            MemberType    Definition
----            ----------    ----------
Equals          Method        bool Equals(System.Object obj)
GetHashCode     Method        int GetHashCode()
GetType         Method        type GetType()
ToString        Method        string ToString()
PSChildName     NoteProperty  string PSChildName=MyKey
PSDrive         NoteProperty  PSDriveInfo PSDrive=HKLM
PSParentPath    NoteProperty  string PSParentPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\MySoftware
PSPath          NoteProperty  string PSPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\MySoftware\MyKey\
PSProvider      NoteProperty  ProviderInfo PSProvider=Microsoft.PowerShell.Core\Registry
MyProperty      NoteProperty  string MyProperty=MyValue

I can then select the property value, split the string and fetch the first object, like so:

PS C:\> ((Get-ItemProperty "HKLM:\SOFTWARE\MySoftware\MyKey\" -Name MyProperty | Get-Member | Where-Object{$_.Name -eq "MyProperty"}).Definition -split " ")[0]

string

I verified that this gives int when I do this with a DWord attribute, but this just doesn't feel like the proper way of finding this information. Is there another, more proper or robust way to find what property type a specific registry key property has?

EDIT: I also just verified that both String and ExpandString return "string" here so there are edge cases where even the above solution does not work.

CodePudding user response：

You can get the type of a property using the .GetType() method:

$value = (Get-ItemProperty 'HKLM:\SOFTWARE\MySoftware\MyKey' -Name MyProperty).MyProperty
$value.GetType().Name   # outputs e. g. "String"

To explicitly test for a given type, use the -is operator:

$value -is [string]   # outputs True if $value is a string

To see how each registry value type maps to a PowerShell type, I've created a registry key that contains values of all possible types and ran the following script:

$props = Get-ItemProperty "HKCU:\test"
$props.PSObject.Properties.Where{ -not $_.Name.StartsWith('PS') }.ForEach{
    [pscustomobject]@{ 'Reg Type' = $_.Name; 'PS Type' = $_.Value.GetType() }
}

Output:

Reg Type      PS Type
--------      -------
REG_DWORD     System.Int32
REG_SZ        System.String
REG_QWORD     System.Int64
REG_BINARY    System.Byte[]
REG_MULTI_SZ  System.String[]
REG_EXPAND_SZ System.String

As you can see both REG_SZ and REG_EXPAND_SZ map to System.String, so you can't differentiate these when you read them using Get-ItemProperty. Instead you would have to use the .NET method RegistryKey.GetValueKind():

$key = Get-Item 'HKLM:\SOFTWARE\MySoftware\MyKey'   # $key is of type RegistryKey
$key.GetValue('MyProperty')      # Output the value
$key.GetValueKind('MyProperty')  # Output the registry type of the value

This outputs "ExpandString" for registry type REG_EXPAND_SZ. For other possible values see RegistryValueKind enum.