Represents a reader that can read a sequential series of characters.
Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public MustInherit Class TextReader
Inherits MarshalByRefObject
Implements IDisposable
Dim instance As TextReader
[SerializableAttribute]
[ComVisibleAttribute(true)]
public abstract class TextReader : MarshalByRefObject, IDisposable
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class TextReader abstract : public MarshalByRefObject, IDisposable
/** @attribute SerializableAttribute() */
/** @attribute ComVisibleAttribute(true) */
public abstract class TextReader extends MarshalByRefObject implements IDisposable
SerializableAttribute
ComVisibleAttribute(true)
public abstract class TextReader extends MarshalByRefObject implements IDisposable
TextReader is the abstract base class of StreamReader and StringReader, which read characters from streams and strings, respectively. Use these derived classes to open a text file for reading a specified range of characters, or to create a reader based on an existing stream.
A derived class must minimally implement the Peek and Read methods in order to make a useful instance of TextReader.
The following code example demonstrates the polymorphic behavior of the TextReader and TextWriter types. Since aStringWriter and aStreamWriter are both TextWriter types, the WriteVowel method is called with both objects and the Write methods associated with each specific type are executed. Similarly, the ReadText method is called with both aStringReader and aStreamReader, and the correct ReadToEnd method is executed. Note that for aStringWriter and aStringReader, the backing store is a string, while a file is the backing store for aStreamWriter and aStreamReader.
Imports System
Imports System.IO
Public Class TextRW
Shared Sub Main()
Dim aStringWriter, aStreamWriter As TextWriter
aStringWriter = New StringWriter()
aStreamWriter = New StreamWriter("InvalidPathChars.txt")
WriteText(aStringWriter)
WriteText(aStreamWriter)
aStreamWriter.Close()
Dim aStringReader, aStreamReader As TextReader
aStringReader = New StringReader(aStringWriter.ToString())
aStreamReader = New StreamReader("InvalidPathChars.txt")
ReadText(aStringReader)
ReadText(aStreamReader)
aStreamReader.Close()
End Sub
Shared Sub WriteText(aTextWriter As TextWriter)
aTextWriter.Write("Invalid file path characters are: ")
aTextWriter.Write(Path.InvalidPathChars)
aTextWriter.Write("."C)
End Sub
Shared Sub ReadText(aTextReader As TextReader)
Console.WriteLine("From {0} - {1}", _
aTextReader.GetType().Name, aTextReader.ReadToEnd())
End Sub
End Class
using System;
using System.IO;
class TextRW
{
static void Main()
{
TextWriter stringWriter = new StringWriter();
using(TextWriter streamWriter =
new StreamWriter("InvalidPathChars.txt"))
{
WriteText(stringWriter);
WriteText(streamWriter);
}
TextReader stringReader =
new StringReader(stringWriter.ToString());
using(TextReader streamReader =
new StreamReader("InvalidPathChars.txt"))
{
ReadText(stringReader);
ReadText(streamReader);
}
}
static void WriteText(TextWriter textWriter)
{
textWriter.Write("Invalid file path characters are: ");
textWriter.Write(Path.InvalidPathChars);
textWriter.Write('.');
}
static void ReadText(TextReader textReader)
{
Console.WriteLine("From {0} - {1}",
textReader.GetType().Name, textReader.ReadToEnd());
}
}
using namespace System;
using namespace System::IO;
void WriteText( TextWriter^ textWriter )
{
textWriter->Write( "Invalid file path characters are: " );
textWriter->Write( Path::InvalidPathChars );
textWriter->Write( Char::Parse( "." ) );
}
void ReadText( TextReader^ textReader )
{
Console::WriteLine( "From {0} - {1}", textReader->GetType()->Name, textReader->ReadToEnd() );
}
int main()
{
TextWriter^ stringWriter = gcnew StringWriter;
TextWriter^ streamWriter = gcnew StreamWriter( "InvalidPathChars.txt" );
WriteText( stringWriter );
WriteText( streamWriter );
streamWriter->Close();
TextReader^ stringReader = gcnew StringReader( stringWriter->ToString() );
TextReader^ streamReader = gcnew StreamReader( "InvalidPathChars.txt" );
ReadText( stringReader );
ReadText( streamReader );
streamReader->Close();
}
import System.*;
import System.IO.*;
class TextRW
{
public static void main(String[] args)
{
TextWriter stringWriter = new StringWriter();
TextWriter streamWriter = new StreamWriter("InvalidPathChars.txt");
try {
WriteText(stringWriter);
WriteText(streamWriter);
}
finally {
streamWriter.Dispose();
}
TextReader stringReader = new StringReader(stringWriter.ToString());
TextReader streamReader = new StreamReader("InvalidPathChars.txt");
try {
ReadText(stringReader);
ReadText(streamReader);
}
finally {
streamReader.Dispose();
}
} //main
static void WriteText(TextWriter textWriter)
{
textWriter.Write("Invalid file path characters are: ");
textWriter.Write(Path.InvalidPathChars);
textWriter.Write('.');
} //WriteText
static void ReadText(TextReader textReader)
{
Console.WriteLine("From {0} - {1}",
textReader.GetType().get_Name(),textReader.ReadToEnd());
} //ReadText
} //TextRW
System.Object
System.MarshalByRefObject
System.IO.TextReader
System.IO.StreamReader
System.IO.StringReader
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
.NET Framework
Supported in: 2.0, 1.1, 1.0
.NET Compact Framework
Supported in: 2.0, 1.0