StreamWriter Constructor (String)

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
)

Parameters

path
Type: System.String

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

ExceptionCondition
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 null.

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();
        }

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
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

ADD
Show:
© 2014 Microsoft