• csharp
• vb

Inheritance Hierarchy

System.Object
System.IO.Stream
System.IO.FileStream
System.IO.MemoryStream
System.IO.UnmanagedMemoryStream
System.Security.Cryptography.CryptoStream

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public MustInherit Class Stream _
 Implements IDisposable

[ComVisibleAttribute(true)]
public abstract class Stream : IDisposable

Constructors

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Properties

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Methods

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Fields

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Remarks

Streams involve three fundamental operations:

1. You can read from streams. Reading is the transfer of data from a stream into a data structure, such as an array of bytes.

2. You can write to streams. Writing is the transfer of data from a data structure into a stream.

3. Streams can support seeking. Seeking is the querying and modifying of the current position within a stream. Seek capability depends on the kind of backing store a stream has. For example, network streams have no unified concept of a current position, and therefore typically do not support seeking.

Stream is the abstract base class of all streams. A stream is an abstraction of a sequence of bytes, such as a file, an input/output device, an inter-process communication pipe, or a TCP/IP socket. The Stream class and its derived classes provide a generic view of these different types of input and output, isolating the programmer from the specific details of the operating system and the underlying devices.

Depending on the underlying data source or repository, streams might support only some of these capabilities. An application can query a stream for its capabilities by using the CanRead, CanWrite, and CanSeek properties.

The Read and Write methods read and write data in a variety of formats. For streams that support seeking, use the Seek and SetLength methods and the Position and Length properties to query and modify the current position and length of a stream.

Some stream implementations perform local buffering of the underlying data to improve performance. For such streams, the Flush method can be used to clear any internal buffers and ensure that all data has been written to the underlying data source or repository.

Calling Close on a Stream flushes any buffered data, essentially calling Flush for you. Close also releases operating system resources such as file handles, network connections, or memory used for any internal buffering.

If you need a stream with no backing store (also known as a bit bucket), use Null.

Notes to Implementers

When implementing a derived class of Stream, you must provide implementations for the Read and Write methods. The asynchronous methods BeginRead, EndRead, BeginWrite, and EndWrite are implemented through the synchronous methods Read and Write. Similarly, your implementations of Read and Write will work correctly with the asynchronous methods. The default implementations of ReadByte and WriteByte create a new single-element byte array, and then call your implementations of Read and Write. When deriving from Stream, if you have an internal byte buffer, it is strongly recommended that you override these methods to access your internal buffer for substantially better performance. You must also provide implementations of CanRead, CanSeek, CanWrite, Flush, Length, Position, Seek, and SetLength.

Do not override the Close method, instead, put all of the Stream cleanup logic in the Dispose method.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference