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SerialPort.Read Method (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.

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

public int Read(
	byte[] buffer,
	int offset,
	int count
)

Parameters

buffer
Type: System.Byte[]

The byte array to write the input to.

offset
Type: System.Int32

The offset in the buffer array to begin reading from.

count
Type: System.Int32

The number of bytes to read.

Return Value

Type: System.Int32
The number of bytes read.

ExceptionCondition
ArgumentNullException

The buffer passed is null.

InvalidOperationException

The specified port is not open.

ArgumentOutOfRangeException

The offset or count parameters are outside a valid region of the buffer being passed. Either offset or count is less than zero.

ArgumentException

offset plus count is greater than the length of the buffer.

TimeoutException

No bytes were available to read.

If it is necessary to switch between reading text and reading binary data from the stream, select a protocol that carefully defines the boundary between text and binary data, such as manually reading bytes and decoding the data.

Because the SerialPort class buffers data, and the stream contained in the BaseStream property does not, the two might conflict about how many bytes are available to read. The BytesToRead property can indicate that there are bytes to read, but these bytes might not be accessible to the stream contained in the BaseStream property because they have been buffered to the SerialPort class.

The Read method does not block other operations when the number of bytes read equals count but there are still unread bytes available on the serial port.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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