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StreamWriter Class
Definition
- Namespace:
- System.IO
- Assemblies:
- mscorlib.dll, System.IO.dll
- Assemblies:
- netstandard.dll, System.Runtime.dll
- Assembly:
- System.IO.dll
- Assembly:
- System.Runtime.Extensions.dll
- Assembly:
- mscorlib.dll
- Assembly:
- netstandard.dll
- Source:
- StreamWriter.cs
- Source:
- StreamWriter.cs
- Source:
- StreamWriter.cs
- Source:
- StreamWriter.cs
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Implements aTextWriter for writing characters to a stream in a particular encoding.
public ref class StreamWriter : System::IO::TextWriterpublic class StreamWriter : System.IO.TextWriter[System.Serializable]public class StreamWriter : System.IO.TextWriter[System.Serializable][System.Runtime.InteropServices.ComVisible(true)]public class StreamWriter : System.IO.TextWritertype StreamWriter = class inherit TextWriter[<System.Serializable>]type StreamWriter = class inherit TextWriter[<System.Serializable>][<System.Runtime.InteropServices.ComVisible(true)>]type StreamWriter = class inherit TextWriterPublic Class StreamWriterInherits TextWriter- Inheritance
- Inheritance
- Attributes
Examples
The following example shows how to use aStreamWriter object to write a file that lists the directories on the C drive, and then uses aStreamReader object to read and display each directory name. A good practice is to use these objects in ausing statement so that the unmanaged resources are correctly disposed. Theusing statement automatically callsDispose on the object when the code that is using it has completed. The constructor used in this example is not supported for use in Windows Store Apps.
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;namespace StreamReadWrite{ class Program { static void Main(string[] args) { // Get the directories currently on the C drive. DirectoryInfo[] cDirs = new DirectoryInfo(@"c:\").GetDirectories(); // Write each directory name to a file. using (StreamWriter sw = new StreamWriter("CDriveDirs.txt")) { foreach (DirectoryInfo dir in cDirs) { sw.WriteLine(dir.Name); } } // Read and show each line from the file. string line = ""; using (StreamReader sr = new StreamReader("CDriveDirs.txt")) { while ((line = sr.ReadLine()) != null) { Console.WriteLine(line); } } } }}Imports System.IOClass Program Shared Sub Main() ' Get the directories currently on the C drive. Dim cDirs As DirectoryInfo() = New DirectoryInfo("c:\").GetDirectories() ' Write each directory name to a file. Using sw As StreamWriter = New StreamWriter("CDriveDirs.txt") For Each Dir As DirectoryInfo In cDirs sw.WriteLine(Dir.Name) Next End Using 'Read and show each line from the file. Dim line As String = "" Using sr As StreamReader = New StreamReader("CDriveDirs.txt") Do line = sr.ReadLine() Console.WriteLine(line) Loop Until line Is Nothing End Using End SubEnd ClassRemarks
StreamWriter is designed for character output in a particular encoding, whereas classes derived fromStream are designed for byte input and output.
Important
This type implements theIDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call itsDispose method in atry/catch block. To dispose of it indirectly, use a language construct such asusing (in C#) orUsing (in Visual Basic). For more information, see the "Using an Object that Implements IDisposable" section in theIDisposable interface topic.
StreamWriter defaults to using an instance ofUTF8Encoding unless specified otherwise. This instance ofUTF8Encoding is constructed without a byte order mark (BOM), so itsGetPreamble method returns an empty byte array. The default UTF-8 encoding for this constructor throws an exception on invalid bytes. This behavior is different from the behavior provided by the encoding object in theEncoding.UTF8 property. To specify a BOM and determine whether an exception is thrown on invalid bytes, use a constructor that accepts an encoding object as a parameter, such asStreamWriter(String, Boolean, Encoding) orStreamWriter.
By default, aStreamWriter is not thread safe. SeeTextWriter.Synchronized for a thread-safe wrapper.
For a list of common I/O tasks, seeCommon I/O Tasks.
Constructors
| Name | Description |
|---|---|
| StreamWriter(Stream, Encoding, Int32, Boolean) | Initializes a new instance of theStreamWriter class for the specified stream by using the specified encoding and buffer size, and optionally leaves the stream open. |
| StreamWriter(Stream, Encoding, Int32) | Initializes a new instance of theStreamWriter class for the specified stream by using the specified encoding and buffer size. |
| StreamWriter(Stream, Encoding) | Initializes a new instance of theStreamWriter class for the specified stream by using the specified encoding and the default buffer size. |
| StreamWriter(Stream) | Initializes a new instance of theStreamWriter class for the specified stream by using UTF-8 encoding and the default buffer size. |
| StreamWriter(String, Boolean, Encoding, Int32) | Initializes a new instance of theStreamWriter 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. |
| StreamWriter(String, Boolean, Encoding) | Initializes a new instance of theStreamWriter class for the specified file by using the specified encoding and default 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. |
| StreamWriter(String, Boolean) | Initializes a new instance of theStreamWriter class for the specified file by 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. |
| StreamWriter(String, Encoding, FileStreamOptions) | Initializes a new instance of theStreamWriter class for the specified file, using the specified encoding, and configured with the specifiedFileStreamOptions object. |
| StreamWriter(String, FileStreamOptions) | Initializes a new instance of theStreamWriter class for the specified file, using the default encoding, and configured with the specifiedFileStreamOptions object. |
| StreamWriter(String) | Initializes a new instance of theStreamWriter class for the specified file by using the default encoding and buffer size. |
Fields
| Name | Description |
|---|---|
| CoreNewLine | Stores the newline characters used for this |
| Null | Provides a |
Properties
| Name | Description |
|---|---|
| AutoFlush | Gets or sets a value indicating whether theStreamWriter will flush its buffer to the underlying stream after every call toWrite(Char). |
| BaseStream | Gets the underlying stream that interfaces with a backing store. |
| Encoding | Gets theEncoding in which the output is written. |
| FormatProvider | Gets an object that controls formatting. (Inherited fromTextWriter) |
| NewLine | Gets or sets the line terminator string used by the current |
Methods
| Name | Description |
|---|---|
| Close() | Closes the current |
| CreateObjRef(Type) | Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited fromMarshalByRefObject) |
| Dispose() | Releases all resources used by theTextWriter object. (Inherited fromTextWriter) |
| Dispose(Boolean) | Causes any buffered data to be written to the underlying stream, releases the unmanaged resources used by theStreamWriter, and optionally the managed resources. |
| DisposeAsync() | Asynchronously writes any buffered data to the underlying stream and releases the unmanaged resources used by theStreamWriter. |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited fromObject) |
| Finalize() | Frees the resources of the currentStreamWriter before it is reclaimed by the garbage collector. |
| Flush() | Clears all buffers for the current writer and causes any buffered data to be written to the underlying stream. |
| FlushAsync() | Clears all buffers for this stream asynchronously and causes any buffered data to be written to the underlying device. |
| FlushAsync(CancellationToken) | Clears all buffers for this stream asynchronously and causes any buffered data to be written to the underlying device. |
| GetHashCode() | Serves as the default hash function. (Inherited fromObject) |
| GetLifetimeService() | Obsolete. Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited fromMarshalByRefObject) |
| GetType() | Gets theType of the current instance. (Inherited fromObject) |
| InitializeLifetimeService() | Obsolete. Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited fromMarshalByRefObject) |
| MemberwiseClone() | Creates a shallow copy of the currentObject. (Inherited fromObject) |
| MemberwiseClone(Boolean) | Creates a shallow copy of the currentMarshalByRefObject object. (Inherited fromMarshalByRefObject) |
| ToString() | Returns a string that represents the current object. (Inherited fromObject) |
| Write(Boolean) | Writes the text representation of a |
| Write(Char) | Writes a character to the stream. |
| Write(Char[], Int32, Int32) | Writes a subarray of characters to the stream. |
| Write(Char[]) | Writes a character array to the stream. |
| Write(Decimal) | Writes the text representation of a decimal value to the text stream. (Inherited fromTextWriter) |
| Write(Double) | Writes the text representation of an 8-byte floating-point value to the text stream. (Inherited fromTextWriter) |
| Write(Int32) | Writes the text representation of a 4-byte signed integer to the text stream. (Inherited fromTextWriter) |
| Write(Int64) | Writes the text representation of an 8-byte signed integer to the text stream. (Inherited fromTextWriter) |
| Write(Object) | Writes the text representation of an object to the text stream by calling the |
| Write(ReadOnlySpan<Char>) | Writes a character span to the stream. |
| Write(Single) | Writes the text representation of a 4-byte floating-point value to the text stream. (Inherited fromTextWriter) |
| Write(String, Object, Object, Object) | Writes a formatted string to the stream, using the same semantics as theFormat(String, Object, Object, Object) method. |
| Write(String, Object, Object, Object) | Writes a formatted string to the text stream, using the same semantics as theFormat(String, Object, Object, Object) method. (Inherited fromTextWriter) |
| Write(String, Object, Object) | Writes a formatted string to the stream using the same semantics as theFormat(String, Object, Object) method. |
| Write(String, Object, Object) | Writes a formatted string to the text stream using the same semantics as theFormat(String, Object, Object) method. (Inherited fromTextWriter) |
| Write(String, Object) | Writes a formatted string to the stream, using the same semantics as theFormat(String, Object) method. |
| Write(String, Object) | Writes a formatted string to the text stream, using the same semantics as theFormat(String, Object) method. (Inherited fromTextWriter) |
| Write(String, Object[]) | Writes a formatted string to the stream, using the same semantics as theFormat(String, Object[]) method. |
| Write(String, Object[]) | Writes a formatted string to the text stream, using the same semantics as theFormat(String, Object[]) method. (Inherited fromTextWriter) |
| Write(String, ReadOnlySpan<Object>) | Writes a formatted string to the stream, using the same semantics asFormat(String, ReadOnlySpan<Object>). |
| Write(String) | Writes a string to the stream. |
| Write(StringBuilder) | Writes a string builder to the text stream. (Inherited fromTextWriter) |
| Write(UInt32) | Writes the text representation of a 4-byte unsigned integer to the text stream. (Inherited fromTextWriter) |
| Write(UInt64) | Writes the text representation of an 8-byte unsigned integer to the text stream. (Inherited fromTextWriter) |
| WriteAsync(Char) | Asynchronously writes a character to the stream. |
| WriteAsync(Char[], Int32, Int32) | Asynchronously writes a subarray of characters to the stream. |
| WriteAsync(Char[]) | Writes a character array to the text stream asynchronously. (Inherited fromTextWriter) |
| WriteAsync(ReadOnlyMemory<Char>, CancellationToken) | Asynchronously writes a character memory region to the stream. |
| WriteAsync(String) | Asynchronously writes a string to the stream. |
| WriteAsync(StringBuilder, CancellationToken) | Asynchronously writes a string builder to the text stream. (Inherited fromTextWriter) |
| WriteLine() | Writes a line terminator to the text stream. (Inherited fromTextWriter) |
| WriteLine(Boolean) | Writes the text representation of a |
| WriteLine(Char) | Writes a character to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Char[], Int32, Int32) | Writes a subarray of characters to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Char[]) | Writes an array of characters to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Decimal) | Writes the text representation of a decimal value to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Double) | Writes the text representation of a 8-byte floating-point value to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Int32) | Writes the text representation of a 4-byte signed integer to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Int64) | Writes the text representation of an 8-byte signed integer to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(Object) | Writes the text representation of an object to the text stream, by calling the |
| WriteLine(ReadOnlySpan<Char>) | Writes the text representation of a character span to the stream, followed by a line terminator. |
| WriteLine(Single) | Writes the text representation of a 4-byte floating-point value to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(String, Object, Object, Object) | Writes out a formatted string and a new line to the stream, using the same semantics asFormat(String, Object). |
| WriteLine(String, Object, Object, Object) | Writes out a formatted string and a new line to the text stream, using the same semantics asFormat(String, Object). (Inherited fromTextWriter) |
| WriteLine(String, Object, Object) | Writes a formatted string and a new line to the stream, using the same semantics as theFormat(String, Object, Object) method. |
| WriteLine(String, Object, Object) | Writes a formatted string and a new line to the text stream, using the same semantics as theFormat(String, Object, Object) method. (Inherited fromTextWriter) |
| WriteLine(String, Object) | Writes a formatted string and a new line to the stream, using the same semantics as theFormat(String, Object) method. |
| WriteLine(String, Object) | Writes a formatted string and a new line to the text stream, using the same semantics as theFormat(String, Object) method. (Inherited fromTextWriter) |
| WriteLine(String, Object[]) | Writes out a formatted string and a new line to the stream, using the same semantics asFormat(String, Object). |
| WriteLine(String, Object[]) | Writes out a formatted string and a new line to the text stream, using the same semantics asFormat(String, Object). (Inherited fromTextWriter) |
| WriteLine(String, ReadOnlySpan<Object>) | Writes out a formatted string and a new line to the stream, using the same semantics asFormat(String, ReadOnlySpan<Object>). |
| WriteLine(String) | Writes a string to the stream, followed by a line terminator. |
| WriteLine(String) | Writes a string to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(StringBuilder) | Writes the text representation of a string builder to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(UInt32) | Writes the text representation of a 4-byte unsigned integer to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLine(UInt64) | Writes the text representation of an 8-byte unsigned integer to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLineAsync() | Asynchronously writes a line terminator to the stream. |
| WriteLineAsync(Char) | Asynchronously writes a character to the stream, followed by a line terminator. |
| WriteLineAsync(Char[], Int32, Int32) | Asynchronously writes a subarray of characters to the stream, followed by a line terminator. |
| WriteLineAsync(Char[]) | Asynchronously writes an array of characters to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
| WriteLineAsync(ReadOnlyMemory<Char>, CancellationToken) | Asynchronously writes the text representation of a character memory region to the stream, followed by a line terminator. |
| WriteLineAsync(String) | Asynchronously writes a string to the stream, followed by a line terminator. |
| WriteLineAsync(StringBuilder, CancellationToken) | Asynchronously writes the text representation of a string builder to the text stream, followed by a line terminator. (Inherited fromTextWriter) |
Explicit Interface Implementations
| Name | Description |
|---|---|
| IDisposable.Dispose() | For a description of this member, seeDispose(). (Inherited fromTextWriter) |
Extension Methods
| Name | Description |
|---|---|
| ConfigureAwait(IAsyncDisposable, Boolean) | Configures how awaits on the tasks returned from an async disposable will be performed. |
Applies to
See also
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