Demonstrate using a nested dispatcher frame to avoid blocking powershell thread (wpf)

wpf.ps1

# demonstrate using a nested dispatcher frame to avoid blocking powershell thread
# this way you can have full "floating" windows manageable interactively in MTA mode (default) powershell
# Oisin/x0n - feb 9, 2009

Set-StrictMode -Version latest

$ps = [powershell]::create()

$rs = [runspacefactory]::createrunspace()
$rs.ApartmentState = "STA"
$rs.ThreadOptions = "ReuseThread"
$rs.Open()

$ps.Runspace = $rs

$null = $ps.AddScript( {

        $xaml = @"
<StackPanel
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>
<TextBox Name="txt1"></TextBox>
<Button Name="btnTest">Test</Button>
<Button Name="btnExit">Exit</Button>
</StackPanel>
"@

        add-type -ass presentationframework, windowsbase -verbose

        $global:exit = $false
        $global:frame = new-object system.windows.threading.dispatcherframe

        $global:handler = { $frame.Continue = $false }
        $global:exitHandler = { $global:exit = $true; $frame.Continue = $false; }

        $stringReader = new-object system.io.StringReader $xaml
        $xmlReader = [system.xml.XmlReader]::Create($stringReader)
        $panel = [system.windows.markup.XamlReader]::Load($xmlReader)

        $button = $panel.FindName("btnTest")
        $button.add_Click( $handler )

        register-objectevent -inputobject $button -eventname Click -action {
            [Diagnostics.Debug]::WriteLine("Test Click") }

        $button = $panel.FindName("btnExit")
        $button.add_Click( $exitHandler )
        
        register-objectevent -inputobject $button -eventname Click -action {
            [Diagnostics.Debug]::WriteLine("Exit Click") }

        $win = new-object system.windows.window
        $win.Content = $panel

        [Diagnostics.Debug]::WriteLine("Showing Window")
        $win.Show();

        while (-not $global:exit) {
            [Diagnostics.Debug]::WriteLine("Pushing Frame")
            [system.windows.threading.dispatcher]::pushframe($frame)
            [Diagnostics.Debug]::WriteLine("Frame Popped")
            $frame.Continue = $true
        }

        [Diagnostics.Debug]::WriteLine("Exiting")
        #$timer.Stop()
        $win.Hide()
    })

$ps
$ps.BeginInvoke()

<#
# clean up async stuff (might want this in a script)

$a[0].endinvoke($a[1])

C:\projects\powershell
[155] > $a[0].Stop()

C:\projects\powershell
[156] > $a[0].runspace.dispose()
#>