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StreamWriter.StreamWriter(String) Constructor

Initializes a new instance of the StreamWriter class for the specified file on the specified path, using the default encoding and buffer size.

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

public StreamWriter (
	string path
)
public StreamWriter (
	String path
)
public function StreamWriter (
	path : String
)
Not applicable.

Parameters

path

The complete file path to write to. path can be a file name.

Exception typeCondition

UnauthorizedAccessException

Access is denied.

ArgumentException

path is an empty string("").

-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.

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.

IOException

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

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. To create a StreamWriter using UTF-8 encoding and a BOM, consider using a constructor that specifies encoding, such as StreamWriter(String,Boolean,Encoding).

The path parameter can be a file name, including a file on a Universal Naming Convention (UNC) share. If the file exists, it is overwritten; otherwise, a new file is created.

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

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 Server 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 Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0
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