Ms Powershell 5: Displaying highlighted item from a Listbox - powershell

Question

I want to be able to display the currently highlighted item from a scrolling list box, without having to click it.
I have set up the list box so that only one item is displayed. The selection changes via the scroll buttons. I want to be able to read the item displayed without having to click it - so .Add_Click is not suitable.
Example code below:
Many thanks
# Listbox test
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing
# set up form
$form = New-Object System.Windows.Forms.Form
$form.Text = "List Box Test"
$form.Size = New-Object System.Drawing.Size(500,200)
$form.StartPosition = "Manual"
$form.Location = New-Object System.Drawing.Point(10, 10)
# Set up list
$List1 = New-Object System.Windows.Forms.ListBox
$List1.Location = New-Object System.Drawing.Point(10, 10)
$List1.Height = 30
$List1.Width = 150
$List1.font = 'arial, 16pt'
[void] $List1.Items.Add('Clubs')
[void] $List1.Items.Add('Diamonds')
[void] $List1.Items.Add('Hearts')
[void] $List1.Items.Add('Spades')
$form.Controls.Add($List1)
# Question: how do I get the highlighted item from the list box to show here, before it is clicked?
# ----------------------------------------------------------------------------------------
# display selection
$TextBox1 = New-Object System.Windows.Forms.TextBox
$TextBox1.Location = New-Object System.Drawing.Point(10,50)
$TextBox1.Size = New-Object System.Drawing.Size(300,30)
$TextBox1.Font = 'arial, 12pt'
$TextBox1.text = "Highlighted item to show here ..."
$form.Controls.Add($TextBox1)
# ----------------------------------------------------------------------------------------
# set up button
$Button1 = New-Object System.Windows.Forms.Button
$Button1.Location = New-Object System.Drawing.Point(10,100)
$Button1.Size = New-Object System.Drawing.Size(50,20)
$Button1.Text = "OK"
$Button1.DialogResult = [System.Windows.Forms.DialogResult]::OK
$form.Controls.Add($Button1)
$form.Topmost = $true
$null = $form.ShowDialog()

Answer 1

Just add a SelectedIndexChanged event handler to the listbox:
$List1.Add_SelectedIndexChanged({
$TextBox1.Text = $this.SelectedItem.ToString() # or do: $this.items[$this.SelectedIndex].ToString()
})
Since a Listbox only contains text, you could leave out the .ToString().
P.S. Don't forget to remove the form from memory when all done with
$form.Dispose()