StreamWriter Constructor (String, Boolean, Encoding, Int32)

Initializes a new instance of the StreamWriter class for the specified file on the specified path, using the specified 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,
	Encoding encoding,
	int bufferSize
)

Parameters

path
Type: System.String

The complete file path to write to.

append
Type: System.Boolean

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.

encoding
Type: System.Text.Encoding

The character encoding to use.

bufferSize
Type: System.Int32

Sets the buffer size.

ExceptionCondition
ArgumentException

path is an empty string ("").

-or-

path contains the name of a system device (com1, com2, etc).

ArgumentNullException

path or encoding is null.

ArgumentOutOfRangeException

bufferSize is negative.

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.

UnauthorizedAccessException

Access is denied.

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.

This constructor initializes the Encoding property using the encoding parameter. For additional information, see Encoding.

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

path is not required to be a file stored on disk; it can be any part of a system that supports access via 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 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();
        }

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, 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, Zune

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: 3.0, 2.0, 1.0
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