StreamReader Constructor (String, Boolean)

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

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

public:
StreamReader(
	String^ path, 
	bool detectEncodingFromByteOrderMarks
)

Parameters

path
Type: System::String

The complete file path to be read.

detectEncodingFromByteOrderMarks
Type: System::Boolean

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

ExceptionCondition
ArgumentException

path is an empty string ("").

ArgumentNullException

path is nullptr.

FileNotFoundException

The file cannot be found.

DirectoryNotFoundException

The specified path is invalid, such as being on an unmapped drive.

IOException

path includes an incorrect or invalid syntax for file name, directory name, or volume label.

This constructor initializes the encoding to UTF8Encoding, the BaseStream property using the stream parameter, and the internal buffer size to 1024 bytes.

The path parameter can be a file name, including a file on a Universal Naming Convention (UNC) share.

The path parameter is not required to be a file stored on disk; it can be any part of a system that supports access using streams.

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 UTF8Encoding is used. See the Encoding::GetPreamble method for more information.

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

The following code example demonstrates this StreamReader constructor.

   void getNewStreamReader()
   {

      //Get a new StreamReader in ASCII format from a 
      //file using a buffer and byte order mark detection
      StreamReader^ srAsciiFromFileFalse512 = gcnew 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
      StreamReader^ srAsciiFromFileFalse = gcnew StreamReader(  "C:\\Temp\\Test.txt",System::Text::Encoding::ASCII,false );

      //Get a new StreamReader in ASCII format from a file 
      StreamReader^ srAsciiFromFile = gcnew StreamReader(  "C:\\Temp\\Test.txt",System::Text::Encoding::ASCII );

      //Get a new StreamReader from a 
      //file with byte order mark detection = false
      StreamReader^ srFromFileFalse = gcnew StreamReader(  "C:\\Temp\\Test.txt",false );

      //Get a new StreamReader from a file
      StreamReader^ srFromFile = gcnew StreamReader(  "C:\\Temp\\Test.txt" );

      //Get a new StreamReader in ASCII format from a 
      //FileStream with byte order mark detection = false and a buffer
      StreamReader^ srAsciiFromStreamFalse512 = gcnew StreamReader( File::OpenRead(  "C:\\Temp\\Test.txt" ),System::Text::Encoding::ASCII,false,512 );

      //Get a new StreamReader in ASCII format from a 
      //FileStream with byte order mark detection = false
      StreamReader^ srAsciiFromStreamFalse = gcnew StreamReader( File::OpenRead(  "C:\\Temp\\Test.txt" ),System::Text::Encoding::ASCII,false );

      //Get a new StreamReader in ASCII format from a FileStream
      StreamReader^ srAsciiFromStream = gcnew StreamReader( File::OpenRead(  "C:\\Temp\\Test.txt" ),System::Text::Encoding::ASCII );

      //Get a new StreamReader from a 
      //FileStream with byte order mark detection = false
      StreamReader^ srFromStreamFalse = gcnew StreamReader( File::OpenRead(  "C:\\Temp\\Test.txt" ),false );

      //Get a new StreamReader from a FileStream
      StreamReader^ srFromStream = gcnew StreamReader( File::OpenRead(  "C:\\Temp\\Test.txt" ) );
   }

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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