SerialPort Class
Represents a serial port resource.
To browse the .NET Framework source code for this type, see the Reference Source.
Assembly: System (in System.dll)
| Name | Description | |
|---|---|---|
![]() | SerialPort() | Initializes a new instance of the SerialPort class. |
![]() | SerialPort(IContainer) | Initializes a new instance of the SerialPort class using the specified IContainer object. |
![]() | SerialPort(String) | Initializes a new instance of the SerialPort class using the specified port name. |
![]() | SerialPort(String, Int32) | Initializes a new instance of the SerialPort class using the specified port name and baud rate. |
![]() | SerialPort(String, Int32, Parity) | Initializes a new instance of the SerialPort class using the specified port name, baud rate, and parity bit. |
![]() | SerialPort(String, Int32, Parity, Int32) | Initializes a new instance of the SerialPort class using the specified port name, baud rate, parity bit, and data bits. |
![]() | SerialPort(String, Int32, Parity, Int32, StopBits) | Initializes a new instance of the SerialPort class using the specified port name, baud rate, parity bit, data bits, and stop bit. |
| Name | Description | |
|---|---|---|
![]() | BaseStream | Gets the underlying Stream object for a SerialPort object. |
![]() | BaudRate | Gets or sets the serial baud rate. |
![]() | BreakState | Gets or sets the break signal state. |
![]() | BytesToRead | Gets the number of bytes of data in the receive buffer. |
![]() | BytesToWrite | Gets the number of bytes of data in the send buffer. |
![]() | CanRaiseEvents | Gets a value indicating whether the component can raise an event.(Inherited from Component.) |
![]() | CDHolding | Gets the state of the Carrier Detect line for the port. |
![]() | Container | Gets the IContainer that contains the Component.(Inherited from Component.) |
![]() | CtsHolding | Gets the state of the Clear-to-Send line. |
![]() | DataBits | Gets or sets the standard length of data bits per byte. |
![]() | DesignMode | |
![]() | DiscardNull | Gets or sets a value indicating whether null bytes are ignored when transmitted between the port and the receive buffer. |
![]() | DsrHolding | Gets the state of the Data Set Ready (DSR) signal. |
![]() | DtrEnable | Gets or sets a value that enables the Data Terminal Ready (DTR) signal during serial communication. |
![]() | Encoding | Gets or sets the byte encoding for pre- and post-transmission conversion of text. |
![]() | Events | |
![]() | Handshake | Gets or sets the handshaking protocol for serial port transmission of data using a value from Handshake. |
![]() | IsOpen | Gets a value indicating the open or closed status of the SerialPort object. |
![]() | NewLine | |
![]() | Parity | Gets or sets the parity-checking protocol. |
![]() | ParityReplace | Gets or sets the byte that replaces invalid bytes in a data stream when a parity error occurs. |
![]() | PortName | Gets or sets the port for communications, including but not limited to all available COM ports. |
![]() | ReadBufferSize | Gets or sets the size of the SerialPort input buffer. |
![]() | ReadTimeout | Gets or sets the number of milliseconds before a time-out occurs when a read operation does not finish. |
![]() | ReceivedBytesThreshold | Gets or sets the number of bytes in the internal input buffer before a DataReceived event occurs. |
![]() | RtsEnable | Gets or sets a value indicating whether the Request to Send (RTS) signal is enabled during serial communication. |
![]() | Site | |
![]() | StopBits | Gets or sets the standard number of stopbits per byte. |
![]() | WriteBufferSize | Gets or sets the size of the serial port output buffer. |
![]() | WriteTimeout | Gets or sets the number of milliseconds before a time-out occurs when a write operation does not finish. |
| Name | Description | |
|---|---|---|
![]() | Close() | |
![]() | CreateObjRef(Type) | Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.) |
![]() | DiscardInBuffer() | Discards data from the serial driver's receive buffer. |
![]() | DiscardOutBuffer() | Discards data from the serial driver's transmit buffer. |
![]() | Dispose() | |
![]() | Dispose(Boolean) | Releases the unmanaged resources used by the SerialPort and optionally releases the managed resources.(Overrides Component.Dispose(Boolean).) |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetLifetimeService() | Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.) |
![]() ![]() | GetPortNames() | Gets an array of serial port names for the current computer. |
![]() | GetService(Type) | |
![]() | GetType() | |
![]() | InitializeLifetimeService() | Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.) |
![]() | MemberwiseClone() | |
![]() | MemberwiseClone(Boolean) | Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.) |
![]() | Open() | Opens a new serial port connection. |
![]() | Read(Byte(), Int32, Int32) | Reads a number of bytes from the SerialPort input buffer and writes those bytes into a byte array at the specified offset. |
![]() | Read(Char(), Int32, Int32) | Reads a number of characters from the SerialPort input buffer and writes them into an array of characters at a given offset. |
![]() | ReadByte() | Synchronously reads one byte from the SerialPort input buffer. |
![]() | ReadChar() | Synchronously reads one character from the SerialPort input buffer. |
![]() | ReadExisting() | Reads all immediately available bytes, based on the encoding, in both the stream and the input buffer of the SerialPort object. |
![]() | ReadLine() | Reads up to the NewLine value in the input buffer. |
![]() | ReadTo(String) | Reads a string up to the specified value in the input buffer. |
![]() | ToString() | |
![]() | Write(Byte(), Int32, Int32) | Writes a specified number of bytes to the serial port using data from a buffer. |
![]() | Write(Char(), Int32, Int32) | Writes a specified number of characters to the serial port using data from a buffer. |
![]() | Write(String) | Writes the specified string to the serial port. |
![]() | WriteLine(String) | Writes the specified string and the NewLine value to the output buffer. |
| Name | Description | |
|---|---|---|
![]() ![]() | InfiniteTimeout | Indicates that no time-out should occur. |
| Name | Description | |
|---|---|---|
![]() | DataReceived | Indicates that data has been received through a port represented by the SerialPort object. |
![]() | Disposed | |
![]() | ErrorReceived | Indicates that an error has occurred with a port represented by a SerialPort object. |
![]() | PinChanged | Indicates that a non-data signal event has occurred on the port represented by the SerialPort object. |
Note |
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To view the .NET Framework source code for this type, see the Reference Source. You can browse through the source code online, download the reference for offline viewing, and step through the sources (including patches and updates) during debugging; see instructions. |
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 Stream object, accessible through the BaseStream property, and passed to classes that wrap or use streams.
The SerialPort class supports the following encodings: ASCIIEncoding, UTF8Encoding, UnicodeEncoding, UTF32Encoding, 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 ReadByte or Write method and perform the encoding yourself.
You use the GetPortNames method to retrieve the valid ports for the current computer.
If a SerialPort object becomes blocked during a read operation, do not abort the thread. Instead, either close the base stream or dispose of the SerialPort object.
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. 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.
' Use this code inside a project created with the Visual Basic > Windows Desktop > Console Application template. ' Replace the default code in Module1.vb with this code. Then right click the project in Solution Explorer, ' select Properties, and set the Startup Object to PortChat. Imports System.IO.Ports Imports System.Threading Public Class PortChat Shared _continue As Boolean Shared _serialPort As SerialPort 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 ' Display Port values and prompt user to enter a port. Public Shared Function SetPortName(defaultPortName As String) As String Dim portName As String Console.WriteLine("Available Ports:") For Each s As String In SerialPort.GetPortNames() Console.WriteLine(" {0}", s) Next Console.Write("Enter COM port value (Default: {0}): ", defaultPortName) portName = Console.ReadLine() If portName = "" OrElse Not (portName.ToLower()).StartsWith("com") Then portName = defaultPortName End If Return portName End Function ' Display BaudRate values and prompt user to enter a value. Public Shared Function SetPortBaudRate(defaultPortBaudRate As Integer) As Integer Dim baudRate As String Console.Write("Baud Rate(default:{0}): ", defaultPortBaudRate) baudRate = Console.ReadLine() If baudRate = "" Then baudRate = defaultPortBaudRate.ToString() End If Return Integer.Parse(baudRate) End Function ' Display PortParity values and prompt user to enter a value. Public Shared Function SetPortParity(defaultPortParity As Parity) As Parity Dim parity As String Console.WriteLine("Available Parity options:") For Each s As String In [Enum].GetNames(GetType(Parity)) Console.WriteLine(" {0}", s) Next Console.Write("Enter Parity value (Default: {0}):", defaultPortParity.ToString(), True) parity = Console.ReadLine() If parity = "" Then parity = defaultPortParity.ToString() End If Return CType([Enum].Parse(GetType(Parity), parity, True), Parity) End Function ' Display DataBits values and prompt user to enter a value. Public Shared Function SetPortDataBits(defaultPortDataBits As Integer) As Integer Dim dataBits As String Console.Write("Enter DataBits value (Default: {0}): ", defaultPortDataBits) dataBits = Console.ReadLine() If dataBits = "" Then dataBits = defaultPortDataBits.ToString() End If Return Integer.Parse(dataBits.ToUpperInvariant()) End Function ' Display StopBits values and prompt user to enter a value. Public Shared Function SetPortStopBits(defaultPortStopBits As StopBits) As StopBits Dim stopBits As String Console.WriteLine("Available StopBits options:") For Each s As String In [Enum].GetNames(GetType(StopBits)) Console.WriteLine(" {0}", s) Next Console.Write("Enter StopBits value (None is not supported and " & vbLf & "raises an ArgumentOutOfRangeException. " & vbLf & " (Default: {0}):", defaultPortStopBits.ToString()) stopBits = Console.ReadLine() If stopBits = "" Then stopBits = defaultPortStopBits.ToString() End If Return CType([Enum].Parse(GetType(StopBits), stopBits, True), StopBits) End Function Public Shared Function SetPortHandshake(defaultPortHandshake As Handshake) As Handshake Dim handshake As String Console.WriteLine("Available Handshake options:") For Each s As String In [Enum].GetNames(GetType(Handshake)) Console.WriteLine(" {0}", s) Next Console.Write("Enter Handshake value (Default: {0}):", defaultPortHandshake.ToString()) handshake = Console.ReadLine() If handshake = "" Then handshake = defaultPortHandshake.ToString() End If Return CType([Enum].Parse(GetType(Handshake), handshake, True), Handshake) End Function End Class
for the ability to call unmanaged code. Associated enumeration: UnmanagedCode
Available since 2.0
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.







