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SerialPort Class

Definition

Namespace:

Assemblies:

System.dll, System.IO.Ports.dll

Represents a serial port resource.

C#Copy

public class SerialPort : System.ComponentModel.Component

Inheritance

SerialPort

Examples

The following code example demonstrates the use of the  class to allow two users to chat from two separate computers connected by a null modem cable. In this example, the users are prompted for the port settings and a username before chatting. Both computers must be executing the program to achieve full functionality of this example.

C#Copy

// Use this code inside a project created with the Visual C# > Windows Desktop > Console Application template.// Replace the code in Program.cs with this code.using System;using System.IO.Ports;using System.Threading; public class PortChat { static bool _continue; static SerialPort _serialPort; 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) { } } } // Display Port values and prompt user to enter a port. public static string SetPortName(string defaultPortName) { string portName; Console.WriteLine("Available Ports:"); foreach (string s in SerialPort.GetPortNames()) { Console.WriteLine(" {0}", s); } Console.Write("Enter COM port value (Default: {0}): ", defaultPortName); portName = Console.ReadLine(); if (portName == "" || !(portName.ToLower()).StartsWith("com")) { portName = defaultPortName; } return portName; } // Display BaudRate values and prompt user to enter a value. public static int SetPortBaudRate(int defaultPortBaudRate) { string baudRate; Console.Write("Baud Rate(default:{0}): ", defaultPortBaudRate); baudRate = Console.ReadLine(); if (baudRate == "") { baudRate = defaultPortBaudRate.ToString(); } return int.Parse(baudRate); } // Display PortParity values and prompt user to enter a value. public static Parity SetPortParity(Parity defaultPortParity) { string parity; Console.WriteLine("Available Parity options:"); foreach (string s in Enum.GetNames(typeof(Parity))) { Console.WriteLine(" {0}", s); } Console.Write("Enter Parity value (Default: {0}):", defaultPortParity.ToString(), true); parity = Console.ReadLine(); if (parity == "") { parity = defaultPortParity.ToString(); } return (Parity)Enum.Parse(typeof(Parity), parity, true); } // Display DataBits values and prompt user to enter a value. public static int SetPortDataBits(int defaultPortDataBits) { string dataBits; Console.Write("Enter DataBits value (Default: {0}): ", defaultPortDataBits); dataBits = Console.ReadLine(); if (dataBits == "") { dataBits = defaultPortDataBits.ToString(); } return int.Parse(dataBits.ToUpperInvariant()); } // Display StopBits values and prompt user to enter a value. public static StopBits SetPortStopBits(StopBits defaultPortStopBits) { string stopBits; Console.WriteLine("Available StopBits options:"); foreach (string s in Enum.GetNames(typeof(StopBits))) { Console.WriteLine(" {0}", s); } Console.Write("Enter StopBits value (None is not supported and \n" + "raises an ArgumentOutOfRangeException. \n (Default: {0}):", defaultPortStopBits.ToString()); stopBits = Console.ReadLine(); if (stopBits == "" ) { stopBits = defaultPortStopBits.ToString(); } return (StopBits)Enum.Parse(typeof(StopBits), stopBits, true); } public static Handshake SetPortHandshake(Handshake defaultPortHandshake) { string handshake; Console.WriteLine("Available Handshake options:"); foreach (string s in Enum.GetNames(typeof(Handshake))) { Console.WriteLine(" {0}", s); } Console.Write("Enter Handshake value (Default: {0}):", defaultPortHandshake.ToString()); handshake = Console.ReadLine(); if (handshake == "") { handshake = defaultPortHandshake.ToString(); } return (Handshake)Enum.Parse(typeof(Handshake), handshake, true); } }

Remarks

Use this class to control a serial port file resource. This class provides synchronous and event-driven I/O, access to pin and break states, and access to serial driver properties. Additionally, the functionality of this class can be wrapped in an internal  object, accessible through the  property, and passed to classes that wrap or use streams.

The  class supports the following encodings: , , , , and any encoding defined in mscorlib.dll where the code page is less than 50000 or the code page is 54936. You can use alternate encodings, but you must use the  or  method and perform the encoding yourself.

You use the  method to retrieve the valid ports for the current computer.

If a  object becomes blocked during a read operation, do not abort the thread. Instead, either close the base stream or dispose of the  object.

Constructors 

	Initializes a new instance of the  class.
	Initializes a new instance of the  class using the specified  object.
	Initializes a new instance of the  class using the specified port name.
	Initializes a new instance of the  class using the specified port name and baud rate.
	Initializes a new instance of the  class using the specified port name, baud rate, and parity bit.
	Initializes a new instance of the  class using the specified port name, baud rate, parity bit, and data bits.
	Initializes a new instance of the  class using the specified port name, baud rate, parity bit, data bits, and stop bit.

Fields 

Indicates that no time-out should occur.

Properties 

	Gets the underlying  object for a  object.
	Gets or sets the serial baud rate.
	Gets or sets the break signal state.
	Gets the number of bytes of data in the receive buffer.
	Gets the number of bytes of data in the send buffer.
	Gets a value indicating whether the component can raise an event. (Inherited from )
	Gets the state of the Carrier Detect line for the port.
	Gets the  that contains the . (Inherited from )
	Gets the state of the Clear-to-Send line.
	Gets or sets the standard length of data bits per byte.
	Gets a value that indicates whether the  is currently in design mode. (Inherited from )
	Gets or sets a value indicating whether null bytes are ignored when transmitted between the port and the receive buffer.
	Gets the state of the Data Set Ready (DSR) signal.
	Gets or sets a value that enables the Data Terminal Ready (DTR) signal during serial communication.
	Gets or sets the byte encoding for pre- and post-transmission conversion of text.
	Gets the list of event handlers that are attached to this . (Inherited from )
	Gets or sets the handshaking protocol for serial port transmission of data using a value from .
	Gets a value indicating the open or closed status of the  object.
	Gets or sets the value used to interpret the end of a call to the  and  methods.
	Gets or sets the parity-checking protocol.
	Gets or sets the byte that replaces invalid bytes in a data stream when a parity error occurs.
	Gets or sets the port for communications, including but not limited to all available COM ports.
	Gets or sets the size of the  input buffer.
	Gets or sets the number of milliseconds before a time-out occurs when a read operation does not finish.
	Gets or sets the number of bytes in the internal input buffer before a  event occurs.
	Gets or sets a value indicating whether the Request to Send (RTS) signal is enabled during serial communication.
	Gets or sets the  of the . (Inherited from )
	Gets or sets the standard number of stopbits per byte.
	Gets or sets the size of the serial port output buffer.
	Gets or sets the number of milliseconds before a time-out occurs when a write operation does not finish.

Methods 

	Closes the port connection, sets the  property to false, and disposes of the internal object.
	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from )
	Discards data from the serial driver's receive buffer.
	Discards data from the serial driver's transmit buffer.
	Releases all resources used by the . (Inherited from )
	Releases the unmanaged resources used by the  and optionally releases the managed resources.
	Determines whether the specified object is equal to the current object. (Inherited from )
	Serves as the default hash function. (Inherited from )
	Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from )
	Gets an array of serial port names for the current computer.
	Returns an object that represents a service provided by the  or by its . (Inherited from )
	Gets the  of the current instance. (Inherited from )
	Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from )
	Creates a shallow copy of the current . (Inherited from )
	Creates a shallow copy of the current  object. (Inherited from )
	Opens a new serial port connection.
	Reads a number of bytes from the  input buffer and writes those bytes into a byte array at the specified offset.
	Reads a number of characters from the  input buffer and writes them into an array of characters at a given offset.
	Synchronously reads one byte from the  input buffer.
	Synchronously reads one character from the  input buffer.
	Reads all immediately available bytes, based on the encoding, in both the stream and the input buffer of the  object.
	Reads up to the  value in the input buffer.
	Reads a string up to the specified value in the input buffer.
	Returns a  containing the name of the , if any. This method should not be overridden. (Inherited from )
	Writes a specified number of bytes to the serial port using data from a buffer.
	Writes a specified number of characters to the serial port using data from a buffer.
	Writes the specified string to the serial port.
	Writes the specified string and the  value to the output buffer.

Events 

	Indicates that data has been received through a port represented by the  object.
	Occurs when the component is disposed by a call to the  method. (Inherited from )
	Indicates that an error has occurred with a port represented by a  object.
	Indicates that a non-data signal event has occurred on the port represented by the  object.

Security

 

for the ability to call unmanaged code. Associated enumeration: