public FrmMainScreen()
{
InitializeComponent();
_schedulerFactory = new StdSchedulerFactory();
}
private void FrmMainScreen_Load(object sender, EventArgs e)
{
start();
}

    private readonly ISchedulerFactory _schedulerFactory;
    private IScheduler _scheduler;

    private async void start()
    {
        _scheduler = await _schedulerFactory.GetScheduler();

        await _scheduler.Start();

        int settime = 20;
        var trigger = TriggerBuilder.Create()
            .WithSimpleSchedule(x => x.WithIntervalInSeconds(settime).RepeatForever())
            .Build();

        var jobDetail = JobBuilder.Create<Jobs>()
            .WithIdentity("Myjob", "group")
            .Build();

        await _scheduler.ScheduleJob(jobDetail, trigger);
    }

    public class Jobs : IJob
    {
        public Task Execute(IJobExecutionContext context)
        {
            return Task.Run(async () =>
              {
                  //这种情况下就不能运行
                  await new FrmMainScreen().Test(12);
              });
        }
    }

    // 将按钮的Click事件，可以正常运行
    private async void button2_Click(object sender, EventArgs e)
    {
       await  Test(12);
    }

    public  async Task Test(int m)
    {
        int result = await TimeConsumingMethodAsnyc(m);
        MessageBox.Show(result.ToString());
    }

    // 用async方法包装耗时函数
    private async Task<int> TimeConsumingMethodAsnyc(int arg)
    {
        return await Task.Run(() => TimeConsumingMethod(arg));
    }

    // 耗时函数
    private int TimeConsumingMethod(int arg)
    {
       Thread.Sleep(5000); // 模拟耗时过程
      //  Task.Delay(5000);
        return arg; // 有返回值
    }
  
}