Query a Windows Installer (MSI) using Powershell

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This is just a quick example of how we can query a Windows Installer using Powershell code:

$msiOpenDatabaseModeReadOnly = 0
$msiOpenDatabaseModeTransact = 1

$windowsInstaller = New-Object -ComObject windowsInstaller.Installer

$pathToMSI = "C:\Users\xxxx\Desktop\AlkaneExample.msi"

$database = $windowsInstaller.GetType().InvokeMember("OpenDatabase", "InvokeMethod", $null, $windowsInstaller, @($pathToMSI, $msiOpenDatabaseModeReadOnly))

$query = "SELECT Property, Value FROM Property"
$propView = $database.GetType().InvokeMember("OpenView", "InvokeMethod", $null, $database, ($query))
$propView.GetType().InvokeMember("Execute", "InvokeMethod", $null, $propView, $null) | Out-Null
$propRecord = $propView.GetType().InvokeMember("Fetch", "InvokeMethod", $null, $propView, $null)
		
while  ($propRecord -ne $null)
{
	$col1 = $propRecord.GetType().InvokeMember("StringData", "GetProperty", $null, $propRecord, 1)
	$col2 = $propRecord.GetType().InvokeMember("StringData", "GetProperty", $null, $propRecord, 2)
 
	write-host $col1 - $col2
	
	#fetch the next record
	$propRecord = $propView.GetType().InvokeMember("Fetch", "InvokeMethod", $null, $propView, $null)	
}

$propView.GetType().InvokeMember("Close", "InvokeMethod", $null, $propView, $null) | Out-Null          
$propView = $null 
$propRecord = $null
$database = $null
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PLEASE NOTE

When writing Powershell functions to return single values (a string, for example) please ensure you pipe any calls to ‘Execute’ or ‘Close’ to ‘Out-Null’ (please see above).  This will stop the function from returning a System.Object[] (since Powershell functions return the whole output from the function, and not just the value after the ‘return’ statement)!