Vista - Events, events

Is it possible to bind PowerShell code to events generated by a Com object?

I'll have a follow-up message with example of what I mean if this is not
clear.

Thanks,
Greg

I'll answer myself that question as best as I can, for the benefit of
others having to deal with the same issue.

Even if you generate an Interop (or already have a PIA) there is no
straightforward way to have a Powershell scriptblock act as event sink
for a COM event (at least at the time).

One reason: PowerShell as it seems, can cast your ScriptBlock only to
EventHandler type. But your COM wrappers for events are not of
EventHandler type.

Example:
>$btn = New-Object System.Windows.Forms.Button
>($btn | get-member | where {$_.Name -eq "add_Click"}).Definition
System.Void add_Click(EventHandler value)

> $a=New-Object -COM Word.Application # with Office PIA installed
> ($a | get-member | where {$_.Name -eq "add_Quit"}).Definition
System.Void add_Quit(ApplicationEvents4_QuitEventHandler )

> $btn.add_Click({"scriptblock"}) # No error
> $a.add_Quit({"scriptblock"})
Cannot convert argument "0", with value: ""scriptblock"", for "add_Quit"
to type "Microsoft.Office.Interop.Word.ApplicationEvents4_QuitEven
tHandler": "Cannot convert value ""scriptblock"" to type
"Microsoft.Office.Interop.Word.ApplicationEvents4_QuitEventHandler".
Error: "Error binding to target method.""

It seems like there is no vanilla PowerShell solution for this at the
time being.

Greg

Greg Borota wrote:
> Is it possible to bind PowerShell code to events generated by a Com object?
>
> I'll have a follow-up message with example of what I mean if this is not
> clear.
>
> Thanks,
> Greg
>
>

The one _possible_ solution I see is native use of the script control.
"Greg Borota" <borota@gmail.com> wrote in message
news:uQe2e4TnGHA.2432@TK2MSFTNGP03.phx.gbl...
> I'll answer myself that question as best as I can, for the benefit of
> others having to deal with the same issue.

A brief coda to this.

There are some "not-quite-native" ways to use COM event handlers, but I
don't yet have an easy way to return the data to PS since I can't
effectively add PS object refs to a script control. What I _can_ do is load
the Script Control into PS, insert some VBScript into it with event handlers
hooked up via GetRef(). See the Add-ActiveScript function for PowerShell
below, and the following GetIeData.txt script following it. To use it, you
do something like this:

Add-ActiveScript <somepath>\GetIeData.txt

Here are the limitations in this current implementation.
+ It's not asynchronous - you cannot load the VBScript into PS and continue
on your way. Window use is effectively blocked until the script exits.
+ This does not return data to the PS session directly. It would be possible
to do on a per-event basis if I can add a reference to the pipeline to the
script, but without that, you either have to raise events directly _or_
capture all events and return them as the result of an invoked function
after the script exits.

==============================

#Add-ActiveScript function
function Add-ActiveScript
{
Param([string]$Path, [string]$Language = 'VBScript')
$sc = New-Object -ComObject ScriptControl
$sc.Language = 'VBScript';
# use FSO to avoid Get-Content's linefeed-eatin' behavior
$fso = New-Object -ComObject Scripting.FileSystemObject
$f = $fso.OpenTextFile($Path, 1, $false, -2)
[void]$sc.AddCode($f.ReadAll())
}

==============================
'Get-IeData.txt
Const READYSTATE_COMPLETE = 4
set ie = CreateObject _
("InternetExplorer.Application")

' Begin Callout A
ie.navigate "about:blank"
Do While ie.ReadyState <> _
READYSTATE_COMPLETE
' Cannot use WScript.* methods w/out WSH as host.
'WScript.Sleep 50
Loop
' End Callout A

' Begin Callout B
dim text
Set text = ie.document. _
createElement("textarea")
text.Value = "type text here"
ie.document.body.AppendChild text
Dim okButton
Set okButton = ie.document. _
createElement("input")
okButton.type = "button"
okButton.value = "OK"
ie.document.body.AppendChild okButton
' End Callout B

' Begin Callout C
Dim Finished: Finished = False
Set okButton.onclick = _
GetRef("OK_Clicked")
' End Callout C

ie.visible = true

' Begin Callout D
Do While Not Finished
MsgBox "This window keeps the script running until IE closed."
Loop
' End Callout D


' Begin Callout E
Sub OK_Clicked()
MsgBox "Text value returned:" & VbCrLf & text.value _
' & vbCrLf & "(IE will exit when this box is closed.)"
Finished = True
ie.Quit

End Sub
' End Callout E