TextWriter Class

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

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

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

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.

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

The following table lists examples of other typical or related I/O tasks.

To do this...

See the example in this topic...

Create a text file.

How to: Write Text to a File

Write to a text file.

How to: Write Text to a File

Read from a text file.

How to: Read Text from a File

Append text to a file.

How to: Open and Append to a Log File



Get the size of a file.


Get the attributes of a file.


Set the attributes of a file.


Determine if a file exists.


Read from a binary file.

How to: Read and Write to a Newly Created Data File

Write to a binary file.

How to: Read and Write to a Newly Created Data File

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.

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 );
   TextReader^ stringReader = gcnew StringReader( stringWriter->ToString() );
   TextReader^ streamReader = gcnew StreamReader(  "InvalidPathChars.txt" );
   ReadText( stringReader );
   ReadText( streamReader );

import System.*;
import System.IO.*;

class TextRW
    public static void main(String[] args)
        TextWriter stringWriter = new StringWriter();
        TextWriter streamWriter = new StreamWriter("InvalidPathChars.txt");
        try {
        finally {
        TextReader stringReader = new StringReader(stringWriter.ToString());
        TextReader streamReader = new StreamReader("InvalidPathChars.txt");
        try {
        finally {
    } //main

    static void WriteText(TextWriter textWriter)
        textWriter.Write("Invalid file path characters are: ");
    } //WriteText

    static void ReadText(TextReader textReader) 
        Console.WriteLine("From {0} - {1}", 
    } //ReadText
} //TextRW

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