Powershell code doesn't work when migrated to a module

Question

Work continues on migrating my HTA to an XAML-based form...

All the controls I require are imported from a file with the XAML in it.

I have added a button and an associated Add_Click event to close the form:

$btnQuit.Add_Click({
Write-Host 'Closing down...' -Fore Red
$Form.Close()
})

That works fine if that code is part of my script.

However, if I move that code to a module as a function like this:

Function DoExit{
    Write-Host 'Closing down...' -Fore Red
    $Form.Close()
}

which the script imports thus:

$Global:ScriptDir = Split-Path -parent $MyInvocation.MyCommand.Path
Import-Module -Name $ScriptDir\\FunctionBlock.psm1 -Verbose -Scope Global

and then try to call it thus:

$btnQuit.Add_Click($function:DoExit)

The error message I get is:

You cannot call a method on a null-valued expression.At [path to my project goes here]FunctionBlock.psm1:20 char:2
+ 
      $Form.Close()
+ 
        ~~~~~~~~~~~~~
  + CategoryInfo          : InvalidOperation: (:) \[\], RuntimeException
  + FullyQualifiedErrorId : InvokeMethodOnNull

My guess is that this is either a scope thing or a syntax thing?

I've tried all manner of combinations of syntax which I've gleaned from this resource and others, to no avail.

Answer 1

@zett42

Thanks for the pointers.

Both of the suggested routes ended up producing the same error but it would seem I hadn't tried every combination of syntax! I changed the Add-Click to this:

$btnQuit.Add_Click({DoExit($Form)}.GetNewClosure())

and the 'DoExit' function to this:

Function DoExit($Form){
    Write-Host 'Closing down...' -Fore Red
    $Form.Close()
}

and it now works!

It seems that I am still unable to vote for posts but, as soon as I can, I will.

Thanks again!