StreamReader Constructor (Stream, Encoding, Boolean)

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding and byte order mark detection option.

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

'Declaration
Public Sub New ( _
	stream As Stream, _
	encoding As Encoding, _
	detectEncodingFromByteOrderMarks As Boolean _
)

Parameters

stream
Type: System.IO.Stream

The stream to be read.

encoding
Type: System.Text.Encoding

The character encoding to use.

detectEncodingFromByteOrderMarks
Type: System.Boolean

Indicates whether to look for byte order marks at the beginning of the file.

ExceptionCondition
ArgumentException

stream does not support reading.

ArgumentNullException

stream or encoding is Nothing.

This constructor initializes the encoding as specified by the encoding parameter, the BaseStream property using the stream parameter, and the internal buffer size to 1024 bytes.

The detectEncodingFromByteOrderMarks parameter detects the encoding by looking at the first three bytes of the stream. It automatically recognizes UTF-8, little-endian Unicode, and big-endian Unicode text if the file starts with the appropriate byte order marks. Otherwise, the user-provided encoding is used. See the Encoding.GetPreamble method for more information.

The StreamReader object calls Dispose on the provided Stream object when StreamReader.Dispose is called.

Caution noteCaution

When you compile a set of characters with a particular cultural setting and retrieve those same characters with a different cultural setting, the characters might not be interpretable, and could cause an exception to be thrown.

For a list of common I/O tasks, see Common I/O Tasks.

The following code example demonstrates this StreamReader constructor.

Private Sub getNewStreamReader()
    Dim S As Stream = File.OpenRead("C:\Temp\Test.txt")
    'Get a new StreamReader in ASCII format from a 
    'file using a buffer and byte order mark detection 
    Dim SrAsciiFromFileFalse512 As StreamReader = New StreamReader("C:\Temp\Test.txt", _
        System.Text.Encoding.ASCII, False, 512)
    'Get a new StreamReader in ASCII format from a 
    'file with byte order mark detection = false 
    Dim SrAsciiFromFileFalse As StreamReader = New StreamReader("C:\Temp\Test.txt", _
        System.Text.Encoding.ASCII, False)
    'Get a new StreamReader in ASCII format from a file  
    Dim SrAsciiFromFile As StreamReader = New StreamReader("C:\Temp\Test.txt", _
        System.Text.Encoding.ASCII)
    'Get a new StreamReader from a 
    'file with byte order mark detection = false         
    Dim SrFromFileFalse As StreamReader = New StreamReader("C:\Temp\Test.txt", False)
    'Get a new StreamReader from a file 
    Dim SrFromFile As StreamReader = New StreamReader("C:\Temp\Test.txt")
    'Get a new StreamReader in ASCII format from a 
    'FileStream with byte order mark detection = false and a buffer 
    Dim SrAsciiFromStreamFalse512 As StreamReader = New StreamReader(S, _
        System.Text.Encoding.ASCII, False, 512)
    'Get a new StreamReader in ASCII format from a 
    'FileStream with byte order mark detection = false 
    Dim SrAsciiFromStreamFalse = New StreamReader(S, _
        System.Text.Encoding.ASCII, False)
    'Get a new StreamReader in ASCII format from a FileStream 
    Dim SrAsciiFromStream As StreamReader = New StreamReader(S, _
        System.Text.Encoding.ASCII)
    'Get a new StreamReader from a 
    'FileStream with byte order mark detection = false 
    Dim SrFromStreamFalse As StreamReader = New StreamReader(S, False)
    'Get a new StreamReader from a FileStream 
    Dim SrFromStream As StreamReader = New StreamReader(S)

End Sub

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, 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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