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Keywords: the main strem
Description: To view the .NET Framework source code for this type, see the Reference Source. You can browse through the source code online, download the reference for offline viewing, and step through the
To view the .NET Framework source code for this type, see the Reference Source. You can browse through the source code online, download the reference for offline viewing, and step through the sources (including patches and updates) during debugging; see instructions .
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, and isolate the programmer from the specific details of the operating system and the underlying devices.
You can read from streams. Reading is the transfer of data from a stream into a data structure, such as an array of bytes.
Streams can support seeking. Seeking refers to querying and modifying 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.
Depending on the underlying data source or repository, streams might support only some of these capabilities. You can query a stream for its capabilities by using the CanRead. CanWrite. and CanSeek properties of the Stream class.
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.
This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try /catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the “Using an Object that Implements IDisposable” section in the IDisposable interface topic.
Disposing a Stream object flushes any buffered data, and essentially calls the Flush method for you. Dispose also releases operating system resources such as file handles, network connections, or memory used for any internal buffering. The BufferedStream class provides the capability of wrapping a buffered stream around another stream in order to improve read and write performance.
Starting with the .NET Framework 4.5, the Stream class includes async methods to simplify asynchronous operations. An async method contains Async in its name, such as ReadAsync. WriteAsync. CopyToAsync. and FlushAsync. These methods enable you to perform resource-intensive I/O operations without blocking the main thread. This performance consideration is particularly important in a Windows 8.x Store app or desktop app where a time-consuming stream operation can block the UI thread and make your app appear as if it is not working. The async methods are used in conjunction with the async and await keywords in Visual Basic and C#.
When used in a Windows 8.x Store app, Stream includes two extension methods: AsInputStream and AsOutputStream. These methods convert a Stream object to a stream in the Windows Runtime. You can also convert a stream in the Windows Runtime to a Stream object by using the AsStreamForRead and AsStreamForWrite methods. For more information, see How to: Convert Between .NET Framework Streams and Windows Runtime Streams
Some stream implementations perform local buffering of the underlying data to improve performance. For such streams, you can use the Flush or FlushAsync method to clear any internal buffers and ensure that all data has been written to the underlying data source or repository.
If you need a stream with no backing store (also known as a bit bucket), use the Null field to retrieve an instance of a stream that is designed for this purpose.
When you implement a derived class of Stream. you must provide implementations for the Read and Write methods. The asynchronous methods ReadAsync. WriteAsync. and CopyToAsync use the synchronous methods Read and Write in their implementations. Therefore, 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 you derive from Stream. we recommend that you override these methods to access your internal buffer, if you have one, 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 the Stream cleanup logic in the Dispose method. For more information, see Implementing a Dispose Method .