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Description

Represents a text writer for a stream. This class provides methods for writing characters to a stream in a buffered manner. It supports encoding and automatic flushing.

StreamWriter is used to write characters to a stream. It is particularly useful when you need to write text data to files or other streams with control over encoding and buffering.

Syntax

public class StreamWriter : TextWriter

Constructors

The StreamWriter class has several constructors to initialize an instance with different parameters, such as the stream, encoding, and whether to flush automatically.

StreamWriter(Stream stream)

Initializes a new instance of the StreamWriter class for the specified stream, using UTF-8 encoding and the buffer size of 1024 bytes.

public StreamWriter(Stream stream);

StreamWriter(Stream stream, Encoding encoding)

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

public StreamWriter(Stream stream,Encoding encoding);

StreamWriter(string path)

Initializes a new instance of the StreamWriter class for the specified file path, using UTF-8 encoding and the default buffer size. If the file exists, it is overwritten.

public StreamWriter(string path);

And many more overloads for various configurations.

Properties

Name Description
AutoFlush Gets or sets a value indicating whether the StreamWriter will flush its buffer to the underlying stream automatically after each write operation.
BaseStream Gets the underlying stream that the StreamWriter is writing to.
Encoding Gets the Encoding in which the output is written.
Format Gets or sets the formatting for the current StreamWriter instance.
NewLine Gets or sets the newline characters, which is \r\n on Windows, \n on Unix, and \r\n on Macintosh.

Methods

StreamWriter inherits many methods from TextWriter, including methods for writing characters, strings, and formatted strings.

Write(char value)

Writes a character to the current stream and flushes the buffer.

public override void Write(char value);

Write(string value)

Writes a string to the current stream and flushes the buffer.

public override void Write(string value);

WriteLine()

Writes a newline character to the stream and flushes the buffer.

public override void WriteLine();

WriteLine(string value)

Writes a string followed by a newline character to the stream and flushes the buffer.

public override void WriteLine(string value);

Flush()

Clears all buffers for the current writer and causes any buffered data to be written to the underlying stream.

public override void Flush();

Close()

Closes the StreamWriter and the underlying stream.

public override void Close();

Example

Writing to a text file

This example demonstrates how to use StreamWriter to write strings to a text file.

using System.IO;
using System.Text;

public class Example
{
    public static void Main(string[] args)
    {
        string filePath = @"c:\temp\myTextFile.txt";
        try
        {
            // Use 'using' statement to ensure the StreamWriter is disposed properly
            using (StreamWriter sw = new StreamWriter(filePath,true))
            {
                sw.WriteLine("This is the first line.");
                sw.Write("This is ");
                sw.WriteLine("a second line with WriteLine.");
                sw.Flush();
            }
        }
        // The file is automatically closed when leaving the 'using' block
    }
}

Requirements

Platform Version
.NET Core 1.0, 2.0, 2.1, 2.2, 3.0, 3.1, 5.0, 6.0, 7.0, 8.0
.NET Framework 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1