Implements a TextReader that reads characters from a byte stream in a particular encoding.
<SerializableAttribute> _ <ComVisibleAttribute(True)> _ Public Class StreamReader _ Inherits TextReader
Dim instance As StreamReader
[SerializableAttribute] [ComVisibleAttribute(true)] public class StreamReader : TextReader
[SerializableAttribute] [ComVisibleAttribute(true)] public ref class StreamReader : public TextReader
public class StreamReader extends TextReader
StreamReader is designed for character input in a particular encoding, whereas the Stream class is designed for byte input and output. Use StreamReader for reading lines of information from a standard text file.
StreamReader defaults to UTF-8 encoding unless specified otherwise, instead of defaulting to the ANSI code page for the current system. UTF-8 handles Unicode characters correctly and provides consistent results on localized versions of the operating system.
By default, a StreamReader is not thread safe. See TextReader..::.Synchronized for a thread-safe wrapper.
The Read(array<Char>[]()[], Int32, Int32) and Write(array<Char>[]()[], Int32, Int32) method overloads read and write the number of characters specified by the count parameter. These are to be distinguished from BufferedStream..::.Read and BufferedStream..::.Write, which read and write the number of bytes specified by the count parameter. Use the BufferedStream methods only for reading and writing an integral number of byte array elements.
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.
For a list of common I/O tasks, see Common I/O Tasks.
The following example uses an instance of StreamReader to read text from a file.
Imports System Imports System.IO Class Test Public Shared Sub Main() Try ' Create an instance of StreamReader to read from a file. Dim sr As StreamReader = New StreamReader("TestFile.txt") Dim line As String ' Read and display the lines from the file until the end ' of the file is reached. Do line = sr.ReadLine() Console.WriteLine(Line) Loop Until line Is Nothing sr.Close() Catch E As Exception ' Let the user know what went wrong. Console.WriteLine("The file could not be read:") Console.WriteLine(E.Message) End Try End Sub End Class
using System; using System.IO; class Test { public static void Main() { try { // Create an instance of StreamReader to read from a file. // The using statement also closes the StreamReader. using (StreamReader sr = new StreamReader("TestFile.txt")) { string line; // Read and display lines from the file until the end of // the file is reached. while ((line = sr.ReadLine()) != null) { Console.WriteLine(line); } } } catch (Exception e) { // Let the user know what went wrong. Console.WriteLine("The file could not be read:"); Console.WriteLine(e.Message); } } }
using namespace System; using namespace System::IO; int main() { try { // Create an instance of StreamReader to read from a file. StreamReader^ sr = gcnew StreamReader( "TestFile.txt" ); try { String^ line; // Read and display lines from the file until the end of // the file is reached. while ( line = sr->ReadLine() ) { Console::WriteLine( line ); } } finally { if ( sr ) delete (IDisposable^)sr; } } catch ( Exception^ e ) { // Let the user know what went wrong. Console::WriteLine( "The file could not be read:" ); Console::WriteLine( e->Message ); } }
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