Program.cs

using Jint;
using Jint.Native;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Markup;
using System.Windows.Threading;

namespace JintJavascriptTest
{
    class Program
    {
        static void Main(string[] args)
        {
            Engine e = new Engine((o) => { o.Strict(); });
            e.SetValue("log", new Action<object>(Console.WriteLine));
            e.SetValue("WindowBuilder", new WindowBuilder());

            e.Execute(
@"var xaml = """";

xaml += ""<Window xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'      "";
xaml += ""        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'                 "";
xaml += ""        xmlns:d='http://schemas.microsoft.com/expression/blend/2008'           "";
xaml += ""        xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006' "";
xaml += ""        mc:Ignorable='d'                                                       "";
xaml += ""        Title='This is title' Height='350' Width='525'>                        "";
xaml += ""    <Grid>                                                                     "";
xaml += ""        <TextBlock FontSize='30'>                                              "";
xaml += ""			ABAbababababab                                                       "";
xaml += ""		</TextBlock>                                                             "";
xaml += ""    </Grid>                                                                    "";
xaml += ""</Window>                                                                      "";


var window = WindowBuilder.Build(xaml);
log(window.Dispatcher.CheckAccess());
log(window.Dispatcher.Invoke);


WindowBuilder.STARun(function(){
    log(1);
    window.Show();
});

WindowBuilder.InvokeRun(window.Dispatcher, function(){
    log(2);
    window.Show();
});

window.Dispatcher.Invoke(function(){
    log(3);
    window.Show();
}, null);


//ShowWindowSafe(window);


function ShowWindowSafe(w)
{
    if (w.Dispatcher.CheckAccess())
        w.Show();
    else
        w.Dispatcher.Invoke(9, function(){w.Show});
}  

"
);
            while(true)
            {
                Thread.Sleep(500);
            }
        }

        internal static void log(object obj)
        {
            return;//for breakpoint
        }
    }

    internal class WindowBuilder
    {
        internal WindowBuilder()
        {
        }

        public Window Build(string xaml)
        {
            try
            {
                byte[] b = Encoding.UTF8.GetBytes(xaml);
                var m = new MemoryStream();
                m.Write(b, 0, b.Length);

                Window w = null;

                Thread thread = new Thread(() =>
                {
                    w = XamlReader.Parse(xaml) as Window;
                    //w.Dispatcher.Invoke();
                    //w.Show(); //test show
                    Thread.Sleep(1);//for breakpoint
                });
                thread.SetApartmentState(ApartmentState.STA);
                thread.Start();
                thread.Join();


                Thread.Sleep(1);//for breakpoint

                return w;
            }
            catch(Exception ex)
            {
                return null;
            }
        }

        public void InvokeRun(Dispatcher dis, Delegate d)
        {

            var t = dis.InvokeAsync(() => { d.DynamicInvoke(JsValue.Undefined, new[] { JsValue.Undefined }); });
            //t.Wait(TimeSpan.FromSeconds(5));
            //seems not woking
            return;
        }

        public void STARun(Delegate d)
        {

            Thread thread = new Thread(() => { d.DynamicInvoke(JsValue.Undefined, new[] { JsValue.Undefined }); });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();
            //not woking
            return;
        }
    }
}