How can I use the unmanaged UI Automation API from PowerShell - powershell

Question

The UI Automation API for Windows is available from two DLLs.
One is a managed DLL, which is C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\UIAutomationClient.dll.
The other is an unmanaged DLL, which is C:\Windows\System32\UIAutomationCore.dll.
According to this post, the unmanaged API is superior to the managed API in terms of the number of visible elements, so I would like to use the unmanaged API.
I have tried three approaches, but all of them failed.
Would you tell me the correct approach?
Approach #1: New-Object -ComObject
$uia = New-Object -ComObject <ProgID of CUIAutomation>
$root = $uia.GetRootElement()
Failed because New-Object requires ProgID but CUIAutomation does not have ProgID.
Approach #2: Instantiation from CLSID
The CLSID of CUIAutomation is ff48dba4-60ef-4201-aa87-54103eef594e, then,
$type = [Type]::GetTypeFromCLSID("ff48dba4-60ef-4201-aa87-54103eef594e")
$uia = [Activator]::CreateInstance($type)
$root = $uia.GetRootElement()
but failed with the following error message.
I still do not know why.
Method invocation failed because [System.__ComObject] does not contain a method named 'GetRootElement'.
At line:1 char:1
+ $root = $uia.GetRootElement()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Approach #3: Add-Type
Add-Type -Path "C:\Windows\System32\UIAutomationCore.dll"
$uia = New-Object UIAutomationClient.CUIAutomation
$root = $uia.GetRootElement()
Failed because Add-Type expects managed DLLs.
Error message:
Add-Type : Could not load file or assembly 'file:///C:\Windows\System32\UIAutomationCore.dll' or one of its dependencies. The module was expected to contain an assembly manifest. At line:1 char:1
+ Add-Type -Path "C:\Windows\System32\UIAutomationCore.dll"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Add-Type], BadImageFormatException
+ FullyQualifiedErrorId : System.BadImageFormatException,Microsoft.PowerShell.Commands.AddTypeCommand
Edit (2018-06-12)
I tried another approach. (and failed)
Approach #4: Interop DLL
I do not really understand what exactly the Interop DLL is, but this post says the Interop DLL helped OP anyway.
I installed Visual Studio and generated Interop.UIAutomationClient.dll by following the procedures of the post.
Add-Type -Path "Interop.UIAutomationClient.dll"
$uia = New-Object UIAutomationClient.CUIAutomationClass
$root = $uia.GetRootElement()
$children = $root.FindAll([UIAutomationClient.TreeScope]::TreeScope_Children, $uia.CreateTrueCondition())
I succeeded in obtaining $root, but failed at the line of $children with the following error message.
Method invocation failed because [System.__ComObject] does not contain a method named 'FindAll'.
At line:1 char:1
+ $children = $root.FindAll([UIAutomationClient.TreeScope]::TreeScope_C ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
I still do not know why.

Answer 1

What about this?:
Add-Type -AssemblyName 'UIAutomationClient'
$ae = [System.Windows.Automation.AutomationElement]
$cTrue = [System.Windows.Automation.PropertyCondition]::TrueCondition
$root = $ae::RootElement
$winNames = $root.FindAll("Children", $cTrue).current.name

Answer 2

I have not yet resolved the problem, but finally found an alternative, that is C# Interactive.
I will leave this question for PowerShell users, but, if you can use C# Interactive as an alternative of PowerShell, the following section may help you.
Approach #5: C# Interactive
Install Visual Studio.
Generate Interop.UIAutomationClient.dll by following the procedures of this post.
Run the following script on csi.exe.
#r "Interop.UIAutomationClient.dll"
var uia = new UIAutomationClient.CUIAutomation();
var root = uia.GetRootElement();
var children = root.FindAll(UIAutomationClient.TreeScope.TreeScope_Children, uia.CreateTrueCondition());
FYI, C# Interactive works if only the following files exist in the same folder (i.e., you can use C# Interactive anywhere just by bringing the following files from the development environment).
C:\Program Files (x86)\MSBuild\14.0\Bin\csi.exe
C:\Program Files (x86)\MSBuild\14.0\Bin\csi.rsp
C:\Program Files (x86)\MSBuild\14.0\Bin\Microsoft.CodeAnalysis.CSharp.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\Microsoft.CodeAnalysis.CSharp.Scripting.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\Microsoft.CodeAnalysis.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\Microsoft.CodeAnalysis.Scripting.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\System.AppContext.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\System.Collections.Immutable.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\System.Diagnostics.StackTrace.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\System.IO.FileSystem.dll
C:\Program Files (x86)\MSBuild\14.0\Bin\System.Reflection.Metadata.dll

Answer 3

Approach 2 you should get to the interface of
IID_IUIAutomation = "{30CBE57D-D9D0-452A-AB13-7AC5AC4825EE}"
CLSID_UIAutomationClient = "{944DE083-8FB8-45CF-BCB7-C477ACB2F897}"
;CoClasses
CLSID_CUIAutomation = "{FF48DBA4-60EF-4201-AA87-54103EEF594E}"
MS Doc states
Remarks
Every UI Automation client application must obtain this interface to a CUIAutomation object in order to gain access to the functionality of UI Automation.
The following example function creates a CUIAutomation object and obtains the
IUIAutomation interface.
IUIAutomation *g_pAutomation;
BOOL InitializeUIAutomation()
{
CoInitialize(NULL);
HRESULT hr = CoCreateInstance(__uuidof(CUIAutomation), NULL, CLSCTX_INPROC_SERVER,
__uuidof(IUIAutomation), (void**)&g_pAutomation);
return (SUCCEEDED(hr));
}
I was not able to get it working in PS but maybe this answers helps partly in the right direction (I have it working in AutoIt but that works differently, you can find it with AutoIt IUIAutomation on google)
$objCUI=[System.Runtime.InteropServices.Marshal]::GetTypeFromCLSID("30CBE57D-D9D0-452A-AB13-7AC5AC4825EE")
or
$Type = [Type]::GetTypeFromCLSID('30CBE57D-D9D0-452A-AB13-7AC5AC4825EE')
$objCUI = [System.Activator]::CreateInstance($Type)
both run but when I come to
$rootEl = $objCUI.GetType().InvokeMember(
"GetRootElement",
"InvokeMethod",
$Null,
$objCUI,
#()
)
I get errors