Embed WinForms in WPF used by PowerShell - wpf

Question

I would like to embed WinForms in WPF used by PowerShell but cannot find good example.
Basically I would like to embed next in WPF:
[System.Windows.Forms.MessageBox]::Show("This is message","MessageBox","YesNo","Question")
I am getting error:
Unexpected 'PROPERTYELEMENT' in parse rule 'NonemptyPropertyElement ::
I am not sure how to insert elements:
("This is message","MessageBox","YesNo","Question")
PowerShell code where I am trying to embed it :
Add-type -AssemblyName PresentationFramework, PresentationCore, System.Windows.Forms, System.Drawing,WindowsFormsIntegration
$ToolboxXml = #"
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:wf="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
Title="Toolbox"
WindowStartupLocation = "CenterScreen"
SizeToContent="Width"
ResizeMode="NoResize"
Topmost="True"
Height="390"
FontFamily="Arial"
WindowStyle="SingleBorderWindow">
<Grid Margin="7 0 7 7" TextOptions.TextRenderingMode="Aliased">
<WindowsFormsHost>
<WindowsFormsHost.Child>
<wf:MessageBox.show x:Name="MessageBox"/>
</WindowsFormsHost.Child>
</WindowsFormsHost>
</Grid>
</Window>
"#
$ToolboxGui = $ToolboxXml -replace 'mc:Ignorable="d"','' -replace "x:N",'N' -replace '^<Win.*', '<Window'
#Load XAML
$Form = [Windows.Markup.XamlReader]::Parse(([string]$ToolboxGui))
[xml]$xaml = $ToolboxGui
$xaml.SelectNodes("//*[#*[contains(translate(name(.),'n','N'),'Name')]]") | ForEach-Object {
New-Variable -Name $_.Name -Value $Form.FindName($_.Name) -Force
}
#$MessageBox = $Form.Findname("MessageBox")
$async = $Form.Dispatcher.InvokeAsync({
$Form.ShowDialog() | Out-Null
})
$async.Wait() | Out-Null