TextWriter Class (System.IO)

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Microsoft Visual Studio 2008/.NET Framework 3.5

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.NET Framework Class Library

TextWriter Class

Updated: November 2007

Represents a writer that can write a sequential series of characters. This class is abstract.

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

Syntax

Visual Basic (Declaration)

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public MustInherit Class TextWriter _
    Inherits MarshalByRefObject _
    Implements IDisposable

Visual Basic (Usage)

Dim instance As TextWriter

[SerializableAttribute]
[ComVisibleAttribute(true)]
public abstract class TextWriter : MarshalByRefObject, 
    IDisposable

Visual C++

[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class TextWriter abstract : public MarshalByRefObject, 
    IDisposable

/** @attribute SerializableAttribute */ 
/** @attribute ComVisibleAttribute(true) */
public abstract class TextWriter extends MarshalByRefObject implements IDisposable

JScript

public abstract class TextWriter extends MarshalByRefObject implements IDisposable

Remarks

TextWriter is the abstract base class of StreamWriter and StringWriter, which write characters to streams and strings, respectively. Create an instance of TextWriter to write an object to a string, write strings to a file, or to serialize XML. You can also use an instance of TextWriter to write text to a custom backing store using the same APIs you would use for a string or a stream, or to add support for text formatting.

All the Write methods of TextWriter having primitive data types as parameters write out the values as strings.

By default, a TextWriter is not thread safe. See TextWriter..::.Synchronized for a thread-safe wrapper.

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

Notes to Inheritors:

A derived class must minimally implement the Write method to make a useful instance of TextWriter.

Examples

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.

Visual Basic

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());
    }
}

Visual C++

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

Inheritance Hierarchy

System..::.Object
  System..::.MarshalByRefObject
    System.IO..::.TextWriter
      System.CodeDom.Compiler..::.IndentedTextWriter
      System.IO..::.StreamWriter
      System.IO..::.StringWriter
      System.Web..::.HttpWriter
      System.Web.UI..::.HtmlTextWriter

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information