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.NET Development
.NET Framework 3.5
System.IO Namespace
StringWriter Class
This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
StringWriter Class

Updated: November 2007

Implements a TextWriter for writing information to a string. The information is stored in an underlying StringBuilder.

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

Visual Basic (Declaration)
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class StringWriter _
    Inherits TextWriter
Visual Basic (Usage)
Dim instance As StringWriter
C#
[SerializableAttribute]
[ComVisibleAttribute(true)]
public class StringWriter : TextWriter
Visual C++
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class StringWriter : public TextWriter
J#
/** @attribute SerializableAttribute */ 
/** @attribute ComVisibleAttribute(true) */
public class StringWriter extends TextWriter
JScript
public class StringWriter extends 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

File..::.AppendText

FileInfo..::.AppendText

Get the size of a file.

FileInfo..::.Length

Get the attributes of a file.

File..::.GetAttributes

Set the attributes of a file.

File..::.SetAttributes

Determine if a file exists.

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 creation of a continuous paragraph from a group of double-spaced sentences, and then the conversion of the paragraph back to the original text.

Visual Basic
Option Explicit
Option Strict

Imports Microsoft.VisualBasic
Imports System
Imports System.IO

Public Class StrReader

    Shared Sub Main()

        Dim textReaderText As String = "TextReader is the " & _
            "abstract base class of StreamReader and " & _
            "StringReader, which read characters from streams " & _
            "and strings, respectively." & _
            vbCrLf & vbCrLf & _
            "Create an instance of TextReader to open a text " & _
            "file for reading a specified range of characters, " & _
            "or to create a reader based on an existing stream." & _
            vbCrLf & vbCrLf & _
            "You can also use an instance of TextReader to read " & _
            "text from a custom backing store using the same " & _
            "APIs you would use for a string or a stream." & _
            vbCrLf & vbCrLf

        Console.WriteLine("Original text:" & vbCrLf & vbCrLf & _
            textReaderText)

        ' From textReaderText, create a continuous paragraph 
        ' with two spaces between each sentence.
        Dim aLine, aParagraph As String
        Dim strReader As New StringReader(textReaderText)
        While True
            aLine = strReader.ReadLine()
            If aLine Is Nothing Then
                aParagraph = aParagraph & vbCrLf
                Exit While
            Else
                aParagraph = aParagraph & aLine & " "
            End If
        End While
        Console.WriteLine("Modified text:" & vbCrLf & vbCrLf & _ 
            aParagraph)

        ' Re-create textReaderText from aParagraph.
        Dim intCharacter As Integer 
        Dim convertedCharacter As Char 
        Dim strWriter As New StringWriter()
        strReader = New StringReader(aParagraph)
        While True
            intCharacter = strReader.Read()

            ' Check for the end of the string 
            ' before converting to a character.
            If intCharacter = -1 Then
                Exit While
            End If

            convertedCharacter = Convert.ToChar(intCharacter)
            If convertedCharacter = "."C Then
                strWriter.Write("." & vbCrLf & vbCrLf)

                ' Bypass the spaces between sentences.
                strReader.Read()
                strReader.Read()
            Else
                strWriter.Write(convertedCharacter)
            End If
        End While
        Console.WriteLine(vbCrLf & "Original text:" & vbCrLf & _ 
            vbCrLf & strWriter.ToString())

    End Sub
End Class

C#
using System;
using System.IO;

class StringRW
{
    static void Main()
    {
        string textReaderText = "TextReader is the abstract base " +
            "class of StreamReader and StringReader, which read " +
            "characters from streams and strings, respectively.\n\n" +

            "Create an instance of TextReader to open a text file " +
            "for reading a specified range of characters, or to " +
            "create a reader based on an existing stream.\n\n" +

            "You can also use an instance of TextReader to read " +
            "text from a custom backing store using the same " +
            "APIs you would use for a string or a stream.\n\n";

        Console.WriteLine("Original text:\n\n{0}", textReaderText);

        // From textReaderText, create a continuous paragraph 
        // with two spaces between each sentence.
        string aLine, aParagraph = null;
        StringReader strReader = new StringReader(textReaderText);
        while(true)
        {
            aLine = strReader.ReadLine();
            if(aLine != null)
            {
                aParagraph = aParagraph + aLine + " ";
            }
            else
            {
                aParagraph = aParagraph + "\n";
                break;
            }
        }
        Console.WriteLine("Modified text:\n\n{0}", aParagraph);

        // Re-create textReaderText from aParagraph.
        int intCharacter;
        char convertedCharacter;
        StringWriter strWriter = new StringWriter();
        strReader = new StringReader(aParagraph);
        while(true)
        {
            intCharacter = strReader.Read();

            // Check for the end of the string 
            // before converting to a character.
            if(intCharacter == -1) break;

            convertedCharacter = Convert.ToChar(intCharacter);
            if(convertedCharacter == '.')
            {
                strWriter.Write(".\n\n");

                // Bypass the spaces between sentences.
                strReader.Read();
                strReader.Read();
            }
            else
            {
                strWriter.Write(convertedCharacter);
            }
        }
        Console.WriteLine("\nOriginal text:\n\n{0}", 
            strWriter.ToString());
    }
}

Visual C++
using namespace System;
using namespace System::IO;
int main()
{
   String^ textReaderText = "TextReader is the abstract base "
   "class of StreamReader and StringReader, which read "
   "characters from streams and strings, respectively.\n\n"
   "Create an instance of TextReader to open a text file "
   "for reading a specified range of characters, or to "
   "create a reader based on an existing stream.\n\n"
   "You can also use an instance of TextReader to read "
   "text from a custom backing store using the same "
   "APIs you would use for a string or a stream.\n\n";
   Console::WriteLine(  "Original text:\n\n{0}", textReaderText );

   // From textReaderText, create a continuous paragraph 
   // with two spaces between each sentence.
      String^ aLine;
   String^ aParagraph;
   StringReader^ strReader = gcnew StringReader( textReaderText );
   while ( true )
   {
      aLine = strReader->ReadLine();
      if ( aLine != nullptr )
      {
         aParagraph = String::Concat( aParagraph, aLine,  " " );
      }
      else
      {
         aParagraph = String::Concat( aParagraph,  "\n" );
         break;
      }
   }

   Console::WriteLine(  "Modified text:\n\n{0}", aParagraph );

   // Re-create textReaderText from aParagraph.
   int intCharacter;
   Char convertedCharacter;
   StringWriter^ strWriter = gcnew StringWriter;
   strReader = gcnew StringReader( aParagraph );
   while ( true )
   {
      intCharacter = strReader->Read();

      // Check for the end of the string 
      // before converting to a character.
      if ( intCharacter == -1 )
            break;


      convertedCharacter = Convert::ToChar( intCharacter );
      if ( convertedCharacter == '.' )
      {
         strWriter->Write(  ".\n\n" );

         // Bypass the spaces between sentences.
         strReader->Read();
         strReader->Read();
      }
      else
      {
         strWriter->Write( convertedCharacter );
      }
   }

   Console::WriteLine(  "\nOriginal text:\n\n{0}", strWriter->ToString() );
}


J#
import System.*;
import System.IO.*;

class StringRW
{
    public static void main(String[] args)
    {
        String textReaderText = "TextReader is the abstract base " 
            + "class of StreamReader and StringReader, which read " 
            + "characters from streams and strings, respectively.\n\n" 
            + "Create an instance of TextReader to open a text file " 
            + "for reading a specified range of characters, or to " 
            + "create a reader based on an existing stream.\n\n" 
            + "You can also use an instance of TextReader to read " 
            + "text from a custom backing store using the same " 
            + "APIs you would use for a string or a stream.\n\n";

        Console.WriteLine("Original text:\n\n{0}", textReaderText);

        // From textReaderText, create a continuous paragraph 
        // with two spaces between each sentence.
        String aParagraph = "";
        String aLine;
        StringReader strReader = new StringReader(textReaderText);
        while (true) {
            aLine = strReader.ReadLine();
            if (aLine != null) {
                aParagraph = aParagraph + aLine + " ";
            }
            else {
                aParagraph = aParagraph + "\n";
                break ;
            }
        }
        Console.WriteLine("Modified text:\n\n{0}", aParagraph);

        // Re-create textReaderText from aParagraph.
        int intCharacter;
        char convertedCharacter;
        StringWriter strWriter = new StringWriter();
        strReader = new StringReader(aParagraph);

        while (true) {
            intCharacter = strReader.Read();

            // Check for the end of the string 
            // before converting to a character.
            if (intCharacter == -1) {
                break ;
            }

            convertedCharacter = Convert.ToChar(intCharacter);
            if (convertedCharacter == '.') {
                strWriter.Write(".\n\n");

                // Bypass the spaces between sentences.
                strReader.Read();
                strReader.Read();
            }

            else {
                strWriter.Write(convertedCharacter);
            }
        }
        Console.WriteLine("\nOriginal text:\n\n{0}", strWriter.ToString());
    } //main
} //StringRW

System..::.Object
  System..::.MarshalByRefObject
    System.IO..::.TextWriter
      System.IO..::.StringWriter
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 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.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 2.0, 1.0
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