StreamReader Constructor (Stream, Boolean)

 

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

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

Public Sub New (
	stream As Stream,
	detectEncodingFromByteOrderMarks As Boolean
)

Parameters

stream
Type: System.IO.Stream

The stream to be read.

detectEncodingFromByteOrderMarks
Type: System.Boolean

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

Exception Condition
ArgumentException

stream does not support reading.

ArgumentNullException

stream is null.

This constructor initializes the encoding to UTF8Encoding, 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. See the Encoding.GetPreamble method for more information.

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

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

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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