var port = new SerialPort("COM2");

var ports = SerialPort.GetPortNames();

var port = new SerialPort("COM2", 115200);

port.WriteTimeout = 1000;
port.ReadTimeout = 1000;

var port = new SerialPort("COM2");
port.Open();
// Do a lot of things here, write, read
port.Close();

byte[] toSend = new byte[] { 0x42, 0xAA, 0x11, 0x00 };
byte[] toReceive = new byte[50];
// this will send the 4 bytes:
port.Write(toSend, 0, toSend.Length);
// This will only send the bytes AA and 11:
port.Write(toSend, 1, 2);
// This will check then number of available bytes to read
var numBytesToRead = port.BytesToRead;
// This will read 50 characters:
port.Read(toReceive, 0, toReceive.Length);
// this will read 10 characters and place them at the offset position 3:
port.Read(toReceive, 3, 10);
// Note: in case of time out while reading or writing, you will receive a TimeoutException
// And you can as well read a single byte:
byte oneByte = port.ReadByte();

string toSend = "I ❤ nanoFramework";
port.WriteLine(toSend);
// this will send the string encoded finishing by a new line, by default `\n`
// You can change the new line to be anything:
port.NewLine = "❤❤";
// Now it will send 2 hearts as the line ending `WriteLine` and will use 2 hearts as the terminator for `ReadLine`.
// You can change it back to the `\n` default at anytime:
port.NewLine = SerialPort.DefaultNewLine; // default is "\n"
// This will read the existing buffer:
string existingString = port.ReadExisting();
// Note that if it can't properly convert the bytes to a string, you'll get an exception
// This will read a full line, it has to be terminated by the NewLine string.
// If nothing is found ending by the NewLine in the ReadTimeout time frame, a TimeoutException will be raised.
string aFullLine = port.ReadLine();

    // Subscribe to the event
    port.DataReceived += DataReceivedNormalEvent;

    // When you're done, you can as well unsubscribe
    port.DataReceived -= DataReceivedNormalEvent;

private void DataReceivedNormalEvent(object sender, SerialDataReceivedEventArgs e)
{
    var ser = (SerialPort)sender;
    // Now you can check how many characters are available, read a line for example
    var numBytesToRead = port.BytesToRead;
    string aFullLine = ser.ReadLine();
}

    port.WatchChar = '\r';
    // Subscribe to the event
    port.DataReceived += DataReceivedNormalEvent;

private void DataReceivedNormalEvent(object sender, SerialDataReceivedEventArgs e)
{
    if (e.EventType == SerialData.WatchChar)
    {
        // The specified character was detected when reading from the serialport.
    }
}