Article
11/18/2011

StreamReader Constructor (Stream, Encoding, Boolean, Int32)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

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

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

Syntax

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

public StreamReader(
    Stream stream,
    Encoding encoding,
    bool detectEncodingFromByteOrderMarks,
    int bufferSize
)

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
true to look for byte order marks at the beginning of the file; otherwise, false.

bufferSize
Type: System.Int32
The minimum buffer size.

Exceptions

Exception	Condition
ArgumentException	The stream does not support reading.
ArgumentNullException	stream or encoding is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException	bufferSize is less than or equal to zero.

Remarks

The buffer size, in number of 16-bit characters, is set by the bufferSize parameter. If bufferSize is less than the minimum allowable size (128 characters), the minimum allowable size is used.

This constructor enables you to change the encoding the first time you read from the StreamReader object. 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 Stream.Dispose() on the provided Stream object when StreamReader.Dispose is called.

Note:
When reading from a Stream, it is more efficient to use a buffer that is the same size as the internal buffer of the stream.

Caution:
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.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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