SerialPort Class

 

Represents a serial port resource.

To browse the .NET Framework source code for this type, see the Reference Source.

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

System.Object
  System.MarshalByRefObject
    System.ComponentModel.Component
      System.IO.Ports.SerialPort

Public Class SerialPort
	Inherits Component

NameDescription
System_CAPS_pubmethodSerialPort()

Initializes a new instance of the SerialPort class.

System_CAPS_pubmethodSerialPort(IContainer)

Initializes a new instance of the SerialPort class using the specified IContainer object.

System_CAPS_pubmethodSerialPort(String)

Initializes a new instance of the SerialPort class using the specified port name.

System_CAPS_pubmethodSerialPort(String, Int32)

Initializes a new instance of the SerialPort class using the specified port name and baud rate.

System_CAPS_pubmethodSerialPort(String, Int32, Parity)

Initializes a new instance of the SerialPort class using the specified port name, baud rate, and parity bit.

System_CAPS_pubmethodSerialPort(String, Int32, Parity, Int32)

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

System_CAPS_pubmethodSerialPort(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.

NameDescription
System_CAPS_pubpropertyBaseStream

Gets the underlying Stream object for a SerialPort object.

System_CAPS_pubpropertyBaudRate

Gets or sets the serial baud rate.

System_CAPS_pubpropertyBreakState

Gets or sets the break signal state.

System_CAPS_pubpropertyBytesToRead

Gets the number of bytes of data in the receive buffer.

System_CAPS_pubpropertyBytesToWrite

Gets the number of bytes of data in the send buffer.

System_CAPS_protpropertyCanRaiseEvents

Gets a value indicating whether the component can raise an event.(Inherited from Component.)

System_CAPS_pubpropertyCDHolding

Gets the state of the Carrier Detect line for the port.

System_CAPS_pubpropertyContainer

Gets the IContainer that contains the Component.(Inherited from Component.)

System_CAPS_pubpropertyCtsHolding

Gets the state of the Clear-to-Send line.

System_CAPS_pubpropertyDataBits

Gets or sets the standard length of data bits per byte.

System_CAPS_protpropertyDesignMode

Gets a value that indicates whether the Component is currently in design mode.(Inherited from Component.)

System_CAPS_pubpropertyDiscardNull

Gets or sets a value indicating whether null bytes are ignored when transmitted between the port and the receive buffer.

System_CAPS_pubpropertyDsrHolding

Gets the state of the Data Set Ready (DSR) signal.

System_CAPS_pubpropertyDtrEnable

Gets or sets a value that enables the Data Terminal Ready (DTR) signal during serial communication.

System_CAPS_pubpropertyEncoding

Gets or sets the byte encoding for pre- and post-transmission conversion of text.

System_CAPS_protpropertyEvents

Gets the list of event handlers that are attached to this Component.(Inherited from Component.)

System_CAPS_pubpropertyHandshake

Gets or sets the handshaking protocol for serial port transmission of data using a value from Handshake.

System_CAPS_pubpropertyIsOpen

Gets a value indicating the open or closed status of the SerialPort object.

System_CAPS_pubpropertyNewLine

Gets or sets the value used to interpret the end of a call to the ReadLine and WriteLine methods.

System_CAPS_pubpropertyParity

Gets or sets the parity-checking protocol.

System_CAPS_pubpropertyParityReplace

Gets or sets the byte that replaces invalid bytes in a data stream when a parity error occurs.

System_CAPS_pubpropertyPortName

Gets or sets the port for communications, including but not limited to all available COM ports.

System_CAPS_pubpropertyReadBufferSize

Gets or sets the size of the SerialPort input buffer.

System_CAPS_pubpropertyReadTimeout

Gets or sets the number of milliseconds before a time-out occurs when a read operation does not finish.

System_CAPS_pubpropertyReceivedBytesThreshold

Gets or sets the number of bytes in the internal input buffer before a DataReceived event occurs.

System_CAPS_pubpropertyRtsEnable

Gets or sets a value indicating whether the Request to Send (RTS) signal is enabled during serial communication.

System_CAPS_pubpropertySite

Gets or sets the ISite of the Component.(Inherited from Component.)

System_CAPS_pubpropertyStopBits

Gets or sets the standard number of stopbits per byte.

System_CAPS_pubpropertyWriteBufferSize

Gets or sets the size of the serial port output buffer.

System_CAPS_pubpropertyWriteTimeout

Gets or sets the number of milliseconds before a time-out occurs when a write operation does not finish.

NameDescription
System_CAPS_pubmethodClose()

Closes the port connection, sets the IsOpen property to false, and disposes of the internal Stream object.

System_CAPS_pubmethodCreateObjRef(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.)

System_CAPS_pubmethodDiscardInBuffer()

Discards data from the serial driver's receive buffer.

System_CAPS_pubmethodDiscardOutBuffer()

Discards data from the serial driver's transmit buffer.

System_CAPS_pubmethodDispose()

Releases all resources used by the Component.(Inherited from Component.)

System_CAPS_protmethodDispose(Boolean)

Releases the unmanaged resources used by the SerialPort and optionally releases the managed resources.(Overrides Component.Dispose(Boolean).)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Releases unmanaged resources and performs other cleanup operations before the Component is reclaimed by garbage collection.(Inherited from Component.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetLifetimeService()

Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodSystem_CAPS_staticGetPortNames()

Gets an array of serial port names for the current computer.

System_CAPS_protmethodGetService(Type)

Returns an object that represents a service provided by the Component or by its Container.(Inherited from Component.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodInitializeLifetimeService()

Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodOpen()

Opens a new serial port connection.

System_CAPS_pubmethodRead(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.

System_CAPS_pubmethodRead(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.

System_CAPS_pubmethodReadByte()

Synchronously reads one byte from the SerialPort input buffer.

System_CAPS_pubmethodReadChar()

Synchronously reads one character from the SerialPort input buffer.

System_CAPS_pubmethodReadExisting()

Reads all immediately available bytes, based on the encoding, in both the stream and the input buffer of the SerialPort object.

System_CAPS_pubmethodReadLine()

Reads up to the NewLine value in the input buffer.

System_CAPS_pubmethodReadTo(String)

Reads a string up to the specified value in the input buffer.

System_CAPS_pubmethodToString()

Returns a String containing the name of the Component, if any. This method should not be overridden.(Inherited from Component.)

System_CAPS_pubmethodWrite(Byte(), Int32, Int32)

Writes a specified number of bytes to the serial port using data from a buffer.

System_CAPS_pubmethodWrite(Char(), Int32, Int32)

Writes a specified number of characters to the serial port using data from a buffer.

System_CAPS_pubmethodWrite(String)

Writes the specified string to the serial port.

System_CAPS_pubmethodWriteLine(String)

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

NameDescription
System_CAPS_pubfieldSystem_CAPS_staticInfiniteTimeout

Indicates that no time-out should occur.

NameDescription
System_CAPS_pubeventDataReceived

Indicates that data has been received through a port represented by the SerialPort object.

System_CAPS_pubeventDisposed

Occurs when the component is disposed by a call to the Dispose method. (Inherited from Component.)

System_CAPS_pubeventErrorReceived

Indicates that an error has occurred with a port represented by a SerialPort object.

System_CAPS_pubeventPinChanged

Indicates that a non-data signal event has occurred on the port represented by the SerialPort object.

System_CAPS_noteNote

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

SecurityPermission

for the ability to call unmanaged code. Associated enumeration: UnmanagedCode

.NET Framework
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.

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