Using variables for events on dynamically generated control - forms

Question

I have a function Add-TextBox, which creates a TextBox control, and assigns a block to it's event handler.
The problem I am facing is that the block is presumably being called with global namespace, and the variables declared inside the Add-TextBox function aren't accessible to it. How do I make them accessible?
Edit: added full code
Add-Type -AssemblyName System.Windows.Forms
Function Add-Control() {
Param (
[System.Windows.Forms.Form]$Form,
[string]$ControlType,
[System.Windows.Forms.Control]$AfterControl = $null,
[int]$Padding = 0
)
$control = New-Object System.Windows.Forms.$ControlType
$control.AutoSize = $true
$x = 5
$y = 5
if ($AfterControl) {
$y = $AfterControl.Location.Y + $AfterControl.Size.Height + $Padding
}
$control.Location = "5,$y"
$form.Controls.Add($control)
return $control
}
Function Add-TextBox() {
Param (
[System.Windows.Forms.Form]$Form,
[string]$Placeholder = "",
[System.Windows.Forms.Control]$AfterControl = $null,
[int]$Padding = 0
)
$control = Add-Control -Form $Form -ControlType "TextBox" -AfterControl $AfterControl -Padding $Padding
$control.Add_GotFocus({
Write-Host "Placeholder is null: $($Placeholder -eq $null)"
if ($this.Text -eq $Placeholder) {
$this.ForeColor = "Black"
$this.Text = ""
}
})
$control.Add_LostFocus({
if ($this.Text -eq "") {
$this.ForeColor = "Darkgray"
$this.Text = $Placeholder
}
})
return $control
}
$form = New-Object system.Windows.Forms.Form
$textbox = Add-TextBox -Form $form -Placeholder "(XXXXXX, npr. 012345)"
$form.ShowDialog()

Answer 1

Seems I can use .GetNewClosure() on script blocks to capture the local variables and retain them.
Add-Type -AssemblyName System.Windows.Forms
Function Add-Control() {
Param (
[System.Windows.Forms.Form]$Form,
[string]$ControlType,
[System.Windows.Forms.Control]$AfterControl = $null,
[int]$Padding = 0
)
$control = New-Object System.Windows.Forms.$ControlType
$control.AutoSize = $true
$x = 5
$y = 5
if ($AfterControl) {
$y = $AfterControl.Location.Y + $AfterControl.Size.Height + $Padding
}
$control.Location = "5,$y"
$form.Controls.Add($control)
return $control
}
Function Add-TextBox() {
Param (
[System.Windows.Forms.Form]$Form,
[string]$Placeholder = "",
[System.Windows.Forms.Control]$AfterControl = $null,
[int]$Padding = 0
)
$control = Add-Control -Form $Form -ControlType "TextBox" -AfterControl $AfterControl -Padding $Padding
$control.Add_GotFocus({
if ($this.Text -eq $Placeholder) {
$this.ForeColor = "Black"
$this.Text = ""
}
}.GetNewClosure()) # Here...
$control.Add_LostFocus({
if ($this.Text -eq "") {
$this.ForeColor = "Darkgray"
$this.Text = $Placeholder
}
}.GetNewClosure()) # And here.
return $control
}
$form = New-Object system.Windows.Forms.Form
$textbox = Add-TextBox -Form $form -Placeholder "(XXXXXX, npr. 012345)"
$form.ShowDialog()