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StreamWriter Constructor (String, Boolean)

Initializes a new instance of the StreamWriter class for the specified file on the specified path, using the default encoding and buffer size. If the file exists, it can be either overwritten or appended to. If the file does not exist, this constructor creates a new file.

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

public StreamWriter (
	string path,
	bool append
)
public StreamWriter (
	String path, 
	boolean append
)
public function StreamWriter (
	path : String, 
	append : boolean
)

Parameters

path

The complete file path to write to.

append

Determines whether data is to be appended to the file. If the file exists and append is false, the file is overwritten. If the file exists and append is true, the data is appended to the file. Otherwise, a new file is created.

Exception typeCondition

UnauthorizedAccessException

Access is denied.

ArgumentException

path is empty.

-or-

path contains the name of a system device (com1, com2, and so on).

ArgumentNullException

path is a null reference (Nothing in Visual Basic).

DirectoryNotFoundException

The specified path is invalid, such as being on an unmapped drive.

IOException

path includes an incorrect or invalid syntax for file name, directory name, or volume label syntax.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

SecurityException

The caller does not have the required permission.

This constructor creates a StreamWriter with UTF-8 encoding without a Byte-Order Mark (BOM), so its GetPreamble method returns an empty byte array. For additional information, see Encoding.

The path parameter can be a file name, including a file on a Universal Naming Convention (UNC) share.

The path parameter is not required to be a file stored on disk; it can be any part of a system that supports access using streams.

Caution noteCaution

When you compile a set of characters with a particular cultural setting and retrieve those same characters with a different cultural setting, the characters might not be interpretable, and could cause an exception to be thrown.

For an example of using this method, see the Example section. 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 StreamWriter constructors.

public void CreateTextFile(string fileName, string textToAdd) 
{
    string logFile = DateTime.Now.ToShortDateString()
        .Replace(@"/",@"-").Replace(@"\",@"-") + ".log";
    
    FileStream fs = new FileStream(fileName,
        FileMode.CreateNew, FileAccess.Write, FileShare.None);
    
    StreamWriter swFromFile = new StreamWriter(logFile);
    swFromFile.Write(textToAdd);
    swFromFile.Flush();
    swFromFile.Close();

    StreamWriter swFromFileStream = new StreamWriter(fs);
    swFromFileStream.Write(textToAdd);
    swFromFileStream.Flush();
    swFromFileStream.Close();

    StreamWriter swFromFileStreamDefaultEnc = 
        new System.IO.StreamWriter(fs, 
        System.Text.Encoding.Default);
    swFromFileStreamDefaultEnc.Write(textToAdd);
    swFromFileStreamDefaultEnc.Flush();
    swFromFileStreamDefaultEnc.Close();

    StreamWriter swFromFileTrue = 
        new StreamWriter(fileName,true);
    swFromFileTrue.Write(textToAdd);
    swFromFileTrue.Flush();
    swFromFileTrue.Close();
    
    StreamWriter swFromFileTrueUTF8Buffer = 
        new StreamWriter(fileName, 
        true, System.Text.Encoding.UTF8,512);
    swFromFileTrueUTF8Buffer.Write(textToAdd);
    swFromFileTrueUTF8Buffer.Flush();
    swFromFileTrueUTF8Buffer.Close();

    StreamWriter swFromFileTrueUTF8 = 
        new StreamWriter(fileName, true,
        System.Text.Encoding.UTF8);
    swFromFileTrueUTF8.Write(textToAdd);
    swFromFileTrueUTF8.Flush();
    swFromFileTrueUTF8.Close();

    StreamWriter swFromFileStreamUTF8Buffer = 
        new StreamWriter(fs, System.Text.Encoding.UTF8, 512);
    swFromFileStreamUTF8Buffer.Write(textToAdd);
    swFromFileStreamUTF8Buffer.Flush();
    swFromFileStreamUTF8Buffer.Close();
}

public void CreateTextFile(String fileName, String textToAdd)
{
    String logFile = DateTime.get_Now().ToShortDateString().
        Replace("/", "-").Replace("\\", "-") + ".log";
    FileStream fs = new FileStream(fileName, FileMode.CreateNew, 
        FileAccess.Write, FileShare.None);
    StreamWriter swFromFile = new StreamWriter(logFile);
    swFromFile.Write(textToAdd);
    swFromFile.Flush();
    swFromFile.Close();
    StreamWriter swFromFileStream = new StreamWriter(fs);
    swFromFileStream.Write(textToAdd);
    swFromFileStream.Flush();
    swFromFileStream.Close();
    StreamWriter swFromFileStreamDefaultEnc = 
        new System.IO.StreamWriter(fs,System.Text.Encoding.get_Default());
    swFromFileStreamDefaultEnc.Write(textToAdd);
    swFromFileStreamDefaultEnc.Flush();
    swFromFileStreamDefaultEnc.Close();
    StreamWriter swFromFileTrue = new StreamWriter(fileName, true);
    swFromFileTrue.Write(textToAdd);
    swFromFileTrue.Flush();
    swFromFileTrue.Close();
    StreamWriter swFromFileTrueUTF8Buffer = new StreamWriter(fileName,
        true, System.Text.Encoding.get_UTF8(), 512);
    swFromFileTrueUTF8Buffer.Write(textToAdd);
    swFromFileTrueUTF8Buffer.Flush();
    swFromFileTrueUTF8Buffer.Close();
    StreamWriter swFromFileTrueUTF8 = new StreamWriter(fileName,
        true, System.Text.Encoding.get_UTF8());
    swFromFileTrueUTF8.Write(textToAdd);
    swFromFileTrueUTF8.Flush();
    swFromFileTrueUTF8.Close();
    StreamWriter swFromFileStreamUTF8Buffer = new StreamWriter(fs,
        System.Text.Encoding.get_UTF8(), 512);
    swFromFileStreamUTF8Buffer.Write(textToAdd);
    swFromFileStreamUTF8Buffer.Flush();
    swFromFileStreamUTF8Buffer.Close();
} //CreateTextFile

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

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