Demonstration of PSObjects, Dispatchers, ScriptBlocks, and SessionStates

unbound.ps1

Add-Type -AssemblyName "WindowsBase"

$synchash = [hashtable]::Synchronized(@{})

$t = "should not get this"

$sb = & {

    @(
        {
            $t
        },
        { <# dummy #> },
        { <# dummy #> }
    )
}
$sb[1] = $sb[0].Ast.GetScriptBlock()
$sb[2] = [scriptblock]::Create( $sb[0].ToString() )

$obj = @(
    (New-Object PSObject),
    (New-Object PSObject),
    (New-Object PSObject)
)
$obj[0] | Add-Member -MemberType ScriptMethod -Name "Method" -Value { $t }
$obj[0] | Add-Member -MemberType ScriptProperty -Name "Property" -Value { $t }
$obj[0] | Add-Member -MemberType ScriptProperty -Name "Selfed" -Value { $this.Property }
$obj[1] | Add-Member -MemberType ScriptMethod -Name "Method" -Value $sb[0].Ast.GetScriptBlock()
$obj[1] | Add-Member -MemberType ScriptProperty -Name "Property" -Value $sb[0].Ast.GetScriptBlock()
$obj[1] | Add-Member -MemberType ScriptProperty -Name "Selfed" -Value { $this.Property }.Ast.GetScriptBlock()
$obj[2] | Add-Member -MemberType ScriptMethod -Name "Method" -Value ( [scriptblock]::Create( $sb[0].ToString() ) )
$obj[2] | Add-Member -MemberType ScriptProperty -Name "Property" -Value ( [scriptblock]::Create( $sb[0].ToString() ) )
$obj[2] | Add-Member -MemberType ScriptProperty -Name "Selfed" -Value ( [scriptblock]::Create( { $this.Property }.ToString() ) )

$synchash.sb = $sb
$synchash.obj = $obj

$dispatchers = [hashtable]::Synchronized(@{})

$end = 0;

while( $end -lt 1 ){
    # get the number of threads user wants to create (default is 1)
      # use console (not WPF) C# for this, because you can't set default values for Read-Host
    $end = Read-Host "How many threads do you want to create? (default: 1)"
    if ( [string]::IsNullOrEmpty( $end ) ){
        $end = 1
    } elseif ( $end -lt 1 ){
        Write-Host "Please enter a number greater than 0"
    }
}

foreach( $i in 1..$end ){

    $script = @(
        "`$dispatchers.Dispatcher$i = [System.Windows.Threading.Dispatcher]::CurrentDispatcher",
        "`$t = `"thread $i`"",
        {
        [void][System.Windows.Threading.Dispatcher]::Run()
        }.ToString()
    ) -join "`n"

    $script = [scriptblock]::Create( $script )

    $runspace = [runspacefactory]::CreateRunspace( $Host )
    $runspace.ApartmentState = "STA"
    $runspace.Name = "thread $i"
    $runspace.ThreadOptions = "ReuseThread"
    $runspace.Open() | Out-Null
    
    $runspace.SessionStateProxy.PSVariable.Set( "synchash", $synchash ) | Out-Null
    $runspace.SessionStateProxy.PSVariable.Set( "dispatchers", $dispatchers ) | Out-Null
    
    $powershell = [powershell]::Create()
    $powershell.Runspace = $runspace

    $powershell.AddScript( $script ) | Out-Null

    $powershell.BeginInvoke() | Out-Null
    
    # ensures dispatchers are set in the correct order
        # we do this instead of $powershell.Invoke() or $powershell.EndInvoke(), because of Dispatcher.Run()
    while( -not $dispatchers."Dispatcher$i" ){
        Start-Sleep -Milliseconds 100
    }

}

$t = "main"

$dispatchers.GetEnumerator() | ForEach-Object {

    $name = $_.Key
    $dispatcher = $_.Value

    Write-Host
    Write-Host "Dispatcher: $name"

    $dispatcher.InvokeAsync({
        Write-Host
        Write-Host "InvokeAsync     - bound"
        Write-Host "`$sb[0].Invoke() - bound:            " $synchash.sb[0].Invoke()
        Write-Host "`$sb[1].Invoke() - unbound(AST):     " $synchash.sb[1].Invoke()
        Write-Host "`$sb[2].Invoke() - unbound(Create()):" $synchash.sb[2].Invoke()
    }) | Out-Null

    $dispatcher.InvokeAsync({
        Write-Host
        Write-Host "InvokeAsync     - unbound"
        Write-Host "`$sb[0].Invoke() - bound:            " $synchash.sb[0].Invoke()
        Write-Host "`$sb[1].Invoke() - unbound(AST):     " $synchash.sb[1].Invoke()
        Write-Host "`$sb[2].Invoke() - unbound(Create()):" $synchash.sb[2].Invoke()
    }.Ast.GetScriptBlock()) | Out-Null

    $dispatcher.InvokeAsync({
        Write-Host
        Write-Host "InvokeAsync    - bound"
        Write-Host "`$obj[0].Method() - bound:            " $synchash.obj[0].Method()
        Write-Host "`$obj[1].Method() - unbound(AST):     " $synchash.obj[1].Method()
        Write-Host "`$obj[2].Method() - unbound(Create()):" $synchash.obj[2].Method()
        Write-Host "`$obj[0].Property - bound:            " $synchash.obj[0].Property
        Write-Host "`$obj[1].Property - unbound(AST):     " $synchash.obj[1].Property
        Write-Host "`$obj[2].Property - unbound(Create()):" $synchash.obj[2].Property
        Write-Host "`$obj[0].Selfed   - bound:            " $synchash.obj[0].Selfed
        Write-Host "`$obj[1].Selfed   - unbound(AST):     " $synchash.obj[1].Selfed
        Write-Host "`$obj[2].Selfed   - unbound(Create()):" $synchash.obj[2].Selfed
    }) | Out-Null

    $output = $dispatcher.InvokeAsync({
        Write-Host
        Write-Host "InvokeAsync    - unbound"
        Write-Host "`$obj[0].Method() - bound:            " $synchash.obj[0].Method()
        Write-Host "`$obj[1].Method() - unbound(AST):     " $synchash.obj[1].Method()
        Write-Host "`$obj[2].Method() - unbound(Create()):" $synchash.obj[2].Method()
        Write-Host "`$obj[0].Property - bound:            " $synchash.obj[0].Property
        Write-Host "`$obj[1].Property - unbound(AST):     " $synchash.obj[1].Property
        Write-Host "`$obj[2].Property - unbound(Create()):" $synchash.obj[2].Property
        Write-Host "`$obj[0].Selfed   - bound:            " $synchash.obj[0].Selfed
        Write-Host "`$obj[1].Selfed   - unbound(AST):     " $synchash.obj[1].Selfed
        Write-Host "`$obj[2].Selfed   - unbound(Create()):" $synchash.obj[2].Selfed
    }.Ast.GetScriptBlock())

    While( -not $output.Task.IsCompleted ){
        # calling GetAwaiter().GetResult() immediately will cause a deadlock
        Start-Sleep -Milliseconds 100
    }
    
    $output.Task.GetAwaiter().GetResult()

    $dispatcher.InvokeShutdown()
}

Write-Host
Write-Host "done"