IronPython ui 线程怎么调用？

在 IronPython 想把 UI 线程和主线程分开，避免被卡死 但是敲好代码后发现代码在 UI 下不起作用？

import wpf
from System.Windows import Application, Window
from threading import Thread
import time

class TiebaClientTools(Window):

    def __init__(self):
        wpf.LoadComponent(self, 'TiebaClientTools.xaml')


        

    def Button_Click(self, sender, e):
        def set_text(num):
            time.sleep(num)
            self.textbox.Text = "new text"
        t = Thread(target=set_text, args=(3,))
        t.start()

if __name__ == '__main__':
    Application().Run(TiebaClientTools())