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StringWriter Constructor (StringBuilder)

Initializes a new instance of the StringWriter class that writes to the specified StringBuilder.

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

public StringWriter(
	StringBuilder sb


Type: System.Text.StringBuilder
The StringBuilder to write to.


sb is null.

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 using the StringBuilder class to modify the underlying string in a closed StringWriter.

using System;
using System.IO;
using System.Text;

class StrWriter
    static void Main()
        StringBuilder strBuilder = 
            new StringBuilder("file path characters are: ");
        StringWriter strWriter = new StringWriter(strBuilder);

            Path.InvalidPathChars, 0, Path.InvalidPathChars.Length);


        // Since the StringWriter is closed, an exception will 
        // be thrown if the Write method is called. However, 
        // the StringBuilder can still manipulate the string.
        strBuilder.Insert(0, "Invalid ");

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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