I guess this is a newbie question. Yet I did not find anything online...

I'm creating a small powershell script with a very simple gui.

This is the relevant part of the script:

foreach ($script in $scripts){
  $btn = New-Object System.Windows.Forms.Button  
  #Text, Location, Size omitted

  #Add clickhandler
  $btn.Add_Click(
    {    
      Write-Host "Clicked on Btn $script"
      Start-Process -FilePath "powershell" -ArgumentList "-command", "`"$script`""
      Write-Host "finished"
      $Form.Close();
    }
  )
  $Form.Controls.Add($btn)
}

Obviously $scripts contains paths pointing towards other powershell scripts. Being a Java developer I was naiv enough to suspect every click handler to be created with its own reference to a script location ($script).

But of course powershell does not evaluate $script until the handler is invoked. Thus, every button will call the last element in my array $scripts since $script will reference the last element in $scripts after the loop completes.

How can I create a click handler inside a foreach-loop based on the loop-variable itself?

Solution

Mathias R. Jessen pointed me to a working solution. .GetNewClosure() called on the handler worked.

Working Code:

foreach ($script in $scripts){
  $btn = New-Object System.Windows.Forms.Button  
  #Text, Location, Size omitted

  #Add clickhandler
  $btn.Add_Click(
    {    
      Write-Host "Clicked on Btn $script"
      Start-Process -FilePath "powershell" -ArgumentList "-command", "`"$script`""
      Write-Host "finished"
      $Form.Close();
    }.GetNewClosure()
  )
  $Form.Controls.Add($btn)
}