控制器中未设置变量值

Question

控制器是：

bool isThreadComplete = false;
public ActionResult generateDoc()
{            
    Thread thread = new Thread(threadSleep);
    thread.Start();
    return Json(true);
}
public void threadSleep()
{
    Thread.Sleep(30000);
    isThreadComplete = true;
}
public ActionResult callThreadSleep() {
    return Json(isThreadComplete);
}

当我使用ajax调用callThreadSleep时，即使在30秒之后它也没有设置变量isThreadComplete的值。任何建议？