WriteLine Method

SerialPort.WriteLine Method

Note: This method is new in the .NET Framework version 2.0.

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

Namespace: System.IO.Ports
Assembly: System (in system.dll)

Public Sub WriteLine ( _
	text As String _
Dim instance As SerialPort
Dim text As String

public void WriteLine (
	String text
public function WriteLine (
	text : String



The string to write to the output buffer.

Exception typeCondition


The str parameter is a null reference (Nothing in Visual Basic).


The specified port is not open.


The WriteLine method could not write to the stream.

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.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

.NET Compact Framework

Supported in: 2.0

Community Additions

© 2015 Microsoft