Arduino 不总是收到来自 Visual Studio 的消息

Question

I have an Arduino Uno which in the Arduino IDE runs code which should receive a message from Visual Studio via Serial Port. If the message is "ON" then lights are on if the message is "OF" then the lights are off.

Sometime it works but sometimes it does not and I don't understand why that is the case.

Here is my Arduino code:

   if (Serial.available())
   {
   
    
    message = Serial.readStringUntil('\n');// reading the message from c#

    
    
    if (message == "ON") // if message is on we go to hazard mode
    {
      state = 1;
      alarmOn = true;
    }
    else if ( message == "OFF") // otherwise we are in the normal mode
    {
      led_state = LOW;
      state = 0;
      alarmOn = false;
    }
  }

Here is my code from Visual Studio

            toggleLEd = !toggleLEd;
            string text = string.Empty;
            if (toggleLEd == true)
            {
                serialPort1.WriteLine("ON");
                Console.WriteLine("ON");
                text = "AlarmOn";
                lbDisplay.Items.Add(text);
            }
            else if(toggleLEd==false)
            {
                serialPort1.WriteLine("OFF");
                Console.WriteLine("OFF");
                text = "AlarmOff";
                lbDisplay.Items.Add(text);

            }

Answer 1

1. is the data transfer rate the same?
2. are you checking whether the port is open? serialPort1.WriteLine("OFF");
3. add it to the Arduino script Serial.println(message); read in VS from serial port and it will be clear to you whether the message was delivered or not