SerialPort.WriteLine(String) Method

Definition

Namespace:

System.IO.Ports

Assembly:

System.IO.Ports.dll

Package:

System.IO.Ports v9.0.0-rc.2.24473.5

Writes the specified string and the NewLine value to the output buffer.

public:
 void WriteLine(System::String ^ text);

public void WriteLine (string text);

member this.WriteLine : string -> unit

Public Sub WriteLine (text As String)

Parameters

text

String

The string to write to the output buffer.

Exceptions

ArgumentNullException

The text parameter is null.

InvalidOperationException

The specified port is not open.

TimeoutException

The WriteLine(String) method could not write to the stream.

Examples

The following code example demonstrates the use of the SerialPort class to allow two users to chat from two separate computers connected by a null modem cable. This code example is part of a larger code example provided for the SerialPort class.

public:
    static void Main()
    {
        String^ name;
        String^ message;
        StringComparer^ stringComparer = StringComparer::OrdinalIgnoreCase;
        Thread^ readThread = gcnew Thread(gcnew ThreadStart(PortChat::Read));

        // Create a new SerialPort object with default settings.
        _serialPort = gcnew SerialPort();

        // Allow the user to set the appropriate properties.
        _serialPort->PortName = SetPortName(_serialPort->PortName);
        _serialPort->BaudRate = SetPortBaudRate(_serialPort->BaudRate);
        _serialPort->Parity = SetPortParity(_serialPort->Parity);
        _serialPort->DataBits = SetPortDataBits(_serialPort->DataBits);
        _serialPort->StopBits = SetPortStopBits(_serialPort->StopBits);
        _serialPort->Handshake = SetPortHandshake(_serialPort->Handshake);

        // Set the read/write timeouts
        _serialPort->ReadTimeout = 500;
        _serialPort->WriteTimeout = 500;

        _serialPort->Open();
        _continue = true;
        readThread->Start();

        Console::Write("Name: ");
        name = Console::ReadLine();

        Console::WriteLine("Type QUIT to exit");

        while (_continue)
        {
            message = Console::ReadLine();

            if (stringComparer->Equals("quit", message))
            {
                _continue = false;
            }
            else
            {
                _serialPort->WriteLine(
                    String::Format("<{0}>: {1}", name, message) );
            }
        }

        readThread->Join();
        _serialPort->Close();
    }

    static void Read()
    {
        while (_continue)
        {
            try
            {
                String^ message = _serialPort->ReadLine();
                Console::WriteLine(message);
            }
            catch (TimeoutException ^) { }
        }
    }

public static void Main()
{
    string name;
    string message;
    StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;
    Thread readThread = new Thread(Read);

    // Create a new SerialPort object with default settings.
    _serialPort = new SerialPort();

    // Allow the user to set the appropriate properties.
    _serialPort.PortName = SetPortName(_serialPort.PortName);
    _serialPort.BaudRate = SetPortBaudRate(_serialPort.BaudRate);
    _serialPort.Parity = SetPortParity(_serialPort.Parity);
    _serialPort.DataBits = SetPortDataBits(_serialPort.DataBits);
    _serialPort.StopBits = SetPortStopBits(_serialPort.StopBits);
    _serialPort.Handshake = SetPortHandshake(_serialPort.Handshake);

    // Set the read/write timeouts
    _serialPort.ReadTimeout = 500;
    _serialPort.WriteTimeout = 500;

    _serialPort.Open();
    _continue = true;
    readThread.Start();

    Console.Write("Name: ");
    name = Console.ReadLine();

    Console.WriteLine("Type QUIT to exit");

    while (_continue)
    {
        message = Console.ReadLine();

        if (stringComparer.Equals("quit", message))
        {
            _continue = false;
        }
        else
        {
            _serialPort.WriteLine(
                String.Format("<{0}>: {1}", name, message));
        }
    }

    readThread.Join();
    _serialPort.Close();
}

public static void Read()
{
    while (_continue)
    {
        try
        {
            string message = _serialPort.ReadLine();
            Console.WriteLine(message);
        }
        catch (TimeoutException) { }
    }
}

Public Shared Sub Main()
    Dim name As String
    Dim message As String
    Dim stringComparer__1 As StringComparer = StringComparer.OrdinalIgnoreCase
    Dim readThread As New Thread(AddressOf Read)

    ' Create a new SerialPort object with default settings.
    _serialPort = New SerialPort()

    ' Allow the user to set the appropriate properties.
    _serialPort.PortName = SetPortName(_serialPort.PortName)
    _serialPort.BaudRate = SetPortBaudRate(_serialPort.BaudRate)
    _serialPort.Parity = SetPortParity(_serialPort.Parity)
    _serialPort.DataBits = SetPortDataBits(_serialPort.DataBits)
    _serialPort.StopBits = SetPortStopBits(_serialPort.StopBits)
    _serialPort.Handshake = SetPortHandshake(_serialPort.Handshake)

    ' Set the read/write timeouts
    _serialPort.ReadTimeout = 500
    _serialPort.WriteTimeout = 500

    _serialPort.Open()
    _continue = True
    readThread.Start()

    Console.Write("Name: ")
    name = Console.ReadLine()

    Console.WriteLine("Type QUIT to exit")

    While _continue
        message = Console.ReadLine()

        If stringComparer__1.Equals("quit", message) Then
            _continue = False
        Else
            _serialPort.WriteLine([String].Format("<{0}>: {1}", name, message))
        End If
    End While

    readThread.Join()
    _serialPort.Close()
End Sub

Public Shared Sub Read()
    While _continue
        Try
            Dim message As String = _serialPort.ReadLine()
            Console.WriteLine(message)
        Catch generatedExceptionName As TimeoutException
        End Try
    End While
End Sub

Remarks

If there are too many bytes in the input buffer and Handshake is set to XOnXOff then the SerialPort object may raise a TimeoutException while it waits for the device to be ready to accept more data.

The written output includes the NewLine string.