WindowInteropHelper Not Returning Handle in Powershell Script

i trying create wpf splash screen windows powershell use when installing software. trying hide close button on form

because don't  want give user ability close form.  have read  not wpf functionality , must done through windows api there several c# examples no powershell ones.   bolded lines script starts fall apart not getting handle form. appreciated.

thanks

add-type -assemblyname presentationframework

$getwindowlong = @'
    [dllimport("user32.dll", entrypoint="getwindowlong")]
    public static extern intptr getwindowlongptr32(
    intptr hwnd,
    int nindex);
'@

    $getwindowlongptr = @'
    [dllimport("user32.dll", entrypoint="getwindowlongptr")]
    public static extern intptr getwindowlongptr64(
    intptr hwnd,
    int nindex);
'@

    $setwindowlong = @'
    [dllimport("user32.dll", entrypoint="setwindowlong")]
    public static extern int setwindowlong32(
    handleref hwnd,
    int nindex,
    int dwnewlong);
'@

    $setwindowlongptr = @'
    [dllimport("user32.dll", entrypoint="setwindowlongptr")]
    private static extern intptr setwindowlongptr64(
    handleref hwnd,
    int nindex,
    intptr dwnewlong);
'@

function getwindowlongptr([intptr]$hwnd,$nindex)
{
    if ([intptr]::size -eq 8)
    {
        #for 64 bit os's
        $fgetwindowlongptr64 = add-type -memberdefinition $getwindowlong -name "win32utils1" -namespace "getwindowlong64" -passthru
        return  $fgetwindowlongptr64::getwindowlongptr64($hwnd, $nindex);

    }
    else
    {
        # 32 bit os's
        $fgetwindowlongptr32 = add-type -memberdefinition $getwindowlong -name "win32utils2" -namespace "getwindowlong32" -passthru
        return  $fgetwindowlongptr32::getwindowlongptr32($hwnd, $nindex);
    }
}

function setwindowlongptr( [intptr]$hwnd, $nindex, $dwnewlong)
{
    if ([intptr]::size -eq 8)
    {
        #for 64 bit os's
        $fsetwindowlong64 = add-type -memberdefinition $setwindowlong -name "win32utils3" -namespace "setwindowlong64" -passthru
        return $fsetwindowlong64::setwindowlongptr64($hwnd, $nindex,$dwnewlong);
    }
    else
    {
        # 32 bit os's
        $fsetwindowlong32 = add-type -memberdefinition $setwindowlong -name "win32utils4" -namespace "setwindowlong32" -passthru
        return $fsetwindowlong32::setwindowlong32($hwnd, $nindex,$dwnewlong);
    }
}

function eventhandler_formload()
{

    $gwl_style         = -16
    $ws_sysmenu     = 0x80000
    set-variable gwl_style -option readonly
    set-variable ws_sysmenu -option readonly

    #here think having trouble handle returning 0
    $myhandlehelper = new-object system.windows.interop.windowinterophelper($form)
    $hwnd = $myhandlehelper.handle

    $test = getwindowlongptr($hwnd,$gwl_style)
     setwindowlongptr($hwnd,$gwl_style, $ws_sysmenu)
}

# ugly splash screen moment
[xml]$xaml = @'
    <window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:name="window"
        title="mainwindow"
        width="500" height="150" topmost="true">
    </window>
'@

$reader=(new-object system.xml.xmlnodereader $xaml)
$form=[windows.markup.xamlreader]::load( $reader )

$handler_load = eventhandler_formload
$form_loaded =$form.add_loaded($handler_load)
$form.showdialog() | out-null

                          

add-type –assemblyname presentationframework add-type –assemblyname presentationcore add-type –assemblyname windowsbase  $code = @" [dllimport("user32.dll", setlasterror = true)]  public static extern int getwindowlong(intptr hwnd, int nindex);  [dllimport("user32.dll")]  public static extern int setwindowlong(intptr hwnd, int nindex, int dwnewlong); "@ add-type -memberdefinition $code -name win32util -namespace system  $gwl_style = -16 $ws_sysmenu = 0x80000  # ugly splash screen moment  [xml]$xaml = @'      <window          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"          x:name="window"          title="mainwindow"          width="500" height="150" topmost="true">      </window> '@   $reader=(new-object system.xml.xmlnodereader $xaml) $form=[windows.markup.xamlreader]::load($reader) $form_loaded =$form.add_loaded({ 	$hwnd = (new-object system.windows.interop.windowinterophelper($this)).handle  	[system.win32util]::setwindowlong($hwnd, $gwl_style, ([system.win32util]::getwindowlong($hwnd, $gwl_style)-band -bnot $ws_sysmenu )) 	})   $form.showdialog() | out-null

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