这里的串口名是serialPort1，定时器名是timerRxInterval

方法1——修改启动方法

private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    Invoke((MethodInvoker)delegate 
    { 
        timerRxInterval.Start(); 
    });
}
private void timerRxInterval_Tick(object sender, EventArgs e)
{
    Console.WriteLine($"enter timerRxInterval_Tick");
    timerRxInterval.Stop();
}

方法2——更改计时器的类型

删除显示界面的定时器

System.Timers.Timer timerRxInterval= new System.Timers.Timer(100);
timerRxInterval.Elapsed += new ElapsedEventHandler(timerRxInterval_Tick);

private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    timerRxInterval.Start(); 
}
private void timerRxInterval_Tick(object sender, EventArgs e)
{
    Console.WriteLine($"enter timerRxInterval_Tick");
    timerRxInterval.Stop();
}

原因

you may have started the timer from another thread, so try invoking it from the correct thread. 

参考

c# - Timer won't tick - Stack Overflow

WinForm Windows.Forms.Timer Start方法无效，Tick 无效，不执行_winform的 tick-CSDN博客