custom event handler which will change Form.Label.Text - multithreading

Question

I'm able to create simple form which displays some text and do some action after button press. Here is my code I'm playing with:
Function Button_Click()
{
[System.Windows.Forms.MessageBox]::Show("Hello World." , "My Dialog Box")
# Parent.Controls["Label1"].Text = "goodbye, world."
}
Function Generate-Form {
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing
# Build font object
$Font = New-Object System.Drawing.Font("Times New Roman",18,[System.Drawing.FontStyle]::Italic)
# Build Button object
$Button = New-Object System.Windows.Forms.Button
$Button.Location = New-Object System.Drawing.Size(35,35)
$Button.Size = New-Object System.Drawing.Size(120,23)
$Button.Text = "Show Dialog Box"
#Add Button event
$Button.Add_Click({Button_Click})
# $Button.Add_Click($Button_Click)
# # Build Label object
$Label = New-Object System.Windows.Forms.Label
$Label.Text = "Firefox status"
$Label.Name = "ffStatus"
$Label.AutoSize = $True
# Build Form object
$Form = New-Object System.Windows.Forms.Form
$Form.Text = "My Form"
$Form.Size = New-Object System.Drawing.Size(200,200)
$Form.StartPosition = "CenterScreen"
$Form.Topmost = $True
# $Form.Font = $Font
# Add button to form
$Form.Controls.Add($Button)
# Add label to form
$Form.Controls.Add($Label)
#Show the Form
$form.ShowDialog()| Out-Null
}
But now I need something more complicated. Let's say I would like to display info on the Form.Label about the status of firefox. I can check whether firefox is running or not
function Get-FirefoxStatus {
$ffRunning = 0
Get-Process| ForEach-Object { if ($_.Name -eq "firefox"){
$ffRunning = 1}
}
Return $ffRunning
}
but how to show the results of Get-FirefoxStatus function inside Form.Label do I need separate thread that will periodically call Get-FirefoxStatus function? Or is there some type of handler which I can register? Or some event loop? Do I need some kind of refresh button? or what to do, is this even possible in powershell?

Answer 1

As promised, here the code you could use to change the label text in the form using a Timer.
Note that I changed the function to get the running status of Firefox to Test-Firefox so now it returns either $true or $false.
I left the Button_Click function unchanged.
function Button_Click() {
[System.Windows.Forms.MessageBox]::Show("Hello World." , "My Dialog Box")
}
function Test-Firefox {
[bool](Get-Process -Name 'firefox' -ErrorAction SilentlyContinue)
}
function Generate-Form {
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing
# create a timer object and set the interval in milliseconds
$timer = New-Object System.Windows.Forms.Timer
$timer.Interval = 1000
# create the Tick event where the text in the label is changed
$timer.Add_Tick({
$Label.Text = if (Test-Firefox) { "Firefox is running" } else { "Firefox is not running" }
})
# Build font object
$Font = New-Object System.Drawing.Font("Times New Roman",18,[System.Drawing.FontStyle]::Italic)
# Build Button object
$Button = New-Object System.Windows.Forms.Button
$Button.Location = New-Object System.Drawing.Size(35,35)
$Button.Size = New-Object System.Drawing.Size(120,23)
$Button.Text = "Show Dialog Box"
#Add Button event
$Button.Add_Click({Button_Click})
# # Build Label object
$Label = New-Object System.Windows.Forms.Label
$Label.Text = if (Test-Firefox) { "Firefox is running" } else { "Firefox is not running" }
$Label.Name = "ffStatus"
$Label.AutoSize = $True
# Build Form object
$Form = New-Object System.Windows.Forms.Form
$Form.Text = "My Form"
$Form.Size = New-Object System.Drawing.Size(200,200)
$Form.StartPosition = "CenterScreen"
$Form.Topmost = $True
# $Form.Font = $Font
# Add button to form
$Form.Controls.Add($Button)
# Add label to form
$Form.Controls.Add($Label)
# Stop and dispose of the timer when the form closes
$Form.Add_Closing({ $timer.Dispose() }) # Dispose() also stops the timer.
# Start the timer and Show the Form
$timer.Start()
$Form.ShowDialog()| Out-Null
# don't forget to dispose of the form when done !
$Form.Dispose()
}
# show the form
Generate-Form