StreamReader Constructor (Stream, Encoding, Boolean, Int32, Boolean)

.NET Framework (current version)

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Initializes a new instance of the StreamReader class for the specified stream based on the specified character encoding, byte order mark detection option, and buffer size, and optionally leaves the stream open.

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

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


Type: System.IO.Stream

The stream to read.

Type: System.Text.Encoding

The character encoding to use.

Type: System.Boolean

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

Type: System.Int32

The minimum buffer size.

Type: System.Boolean

true to leave the stream open after the StreamReader object is disposed; otherwise, false.

Unless you set the leaveOpen parameter to true, the StreamReader object calls Dispose() on the provided Stream object when StreamReader.Dispose is called.

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. If the detectEncodingFromByteOrderMarks parameter is true, the constructor detects the encoding by looking at the first three bytes of the stream. It automatically recognizes UTF-8, little-endian Unicode, little-endian UTF-32, big-endian Unicode, and big-endian UTF-32 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.


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.


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 interpreted correctly, and could cause an exception to be thrown.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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