Artigo
11/18/2011

MemoryStream Class

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Creates a stream whose backing store is memory.

Inheritance Hierarchy

System.Object
System.IO.Stream
System.IO.MemoryStream

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public Class MemoryStream _
    Inherits Stream

[ComVisibleAttribute(true)]
public class MemoryStream : Stream

The MemoryStream type exposes the following members.

Constructors

	Name	Description
	MemoryStream()	Initializes a new instance of the MemoryStream class with an expandable capacity initialized to zero.
	MemoryStream(array<Byte[])	Initializes a new non-resizable instance of the MemoryStream class based on the specified byte array.
	MemoryStream(Int32)	Initializes a new instance of the MemoryStream class with an expandable capacity initialized as specified.
	MemoryStream(array<Byte[], Boolean)	Initializes a new non-resizable instance of the MemoryStream class based on the specified byte array with the CanWrite property set as specified.
	MemoryStream(array<Byte[], Int32, Int32)	Initializes a new non-resizable instance of the MemoryStream class based on the specified region (index) of a byte array.
	MemoryStream(array<Byte[], Int32, Int32, Boolean)	Initializes a new non-resizable instance of the MemoryStream class based on the specified region of a byte array, with the CanWrite property set as specified.
	MemoryStream(array<Byte[], Int32, Int32, Boolean, Boolean)	Initializes a new instance of the MemoryStream class based on the specified region of a byte array, with the CanWrite property set as specified, and the ability to call GetBuffer set as specified.

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Properties

	Name	Description
	CanRead	Gets a value indicating whether the current stream supports reading. (Overrides Stream.CanRead.)
	CanSeek	Gets a value indicating whether the current stream supports seeking. (Overrides Stream.CanSeek.)
	CanTimeout	Gets a value that determines whether the current stream can time out. (Inherited from Stream.)
	CanWrite	Gets a value indicating whether the current stream supports writing. (Overrides Stream.CanWrite.)
	Capacity	Gets or sets the number of bytes allocated for this stream.
	Length	Gets the length of the stream in bytes. (Overrides Stream.Length.)
	Position	Gets or sets the current position within the stream. (Overrides Stream.Position.)
	ReadTimeout	Gets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out. (Inherited from Stream.)
	WriteTimeout	Gets or sets a value, in miliseconds, that determines how long the stream will attempt to write before timing out. (Inherited from Stream.)

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Methods

	Name	Description
	BeginRead	Begins an asynchronous read operation. (Inherited from Stream.)
	BeginWrite	Begins an asynchronous write operation. (Inherited from Stream.)
	Close	Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. (Inherited from Stream.)
	CopyTo(Stream)	Reads all the bytes from the current stream and writes them to the destination stream. (Inherited from Stream.)
	CopyTo(Stream, Int32)	Reads all the bytes from the current stream and writes them to a destination stream, using a specified buffer size. (Inherited from Stream.)
	Dispose()	Releases all resources used by the Stream. (Inherited from Stream.)
	Dispose(Boolean)	Releases the unmanaged resources used by the MemoryStream class and optionally releases the managed resources. (Overrides Stream.Dispose(Boolean).)
	EndRead	Waits for the pending asynchronous read to complete. (Inherited from Stream.)
	EndWrite	Ends an asynchronous write operation. (Inherited from Stream.)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	Flush	Overrides Stream.Flush so that no action is performed. (Overrides Stream.Flush().)
	GetBuffer	Returns the array of unsigned bytes from which this stream was created.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Read	Reads a block of bytes from the current stream and writes the data to a buffer. (Overrides Stream.Read(array<Byte[], Int32, Int32).)
	ReadByte	Reads a byte from the current stream. (Overrides Stream.ReadByte().)
	Seek	Sets the position within the current stream to the specified value. (Overrides Stream.Seek(Int64, SeekOrigin).)
	SetLength	Sets the length of the current stream to the specified value. (Overrides Stream.SetLength(Int64).)
	ToArray	Writes the stream contents to a byte array, regardless of the Position property.
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	Write	Writes a block of bytes to the current stream using data read from a buffer. (Overrides Stream.Write(array<Byte[], Int32, Int32).)
	WriteByte	Writes a byte to the current stream at the current position. (Overrides Stream.WriteByte(Byte).)
	WriteTo	Writes the entire contents of this memory stream to another stream.

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Remarks

The MemoryStream class creates streams that have memory as a backing store instead of a disk or a network connection. MemoryStream encapsulates data stored as an unsigned byte array that is initialized upon creation of a MemoryStream object, or the array can be created as empty. The encapsulated data is directly accessible in memory. Memory streams can reduce the need for temporary buffers and files in an application.

The current position of a stream is the position at which the next read or write operation could take place. The current position can be retrieved or set through the Seek method. When a new instance of MemoryStream is created, the current position is set to zero.

Memory streams created with an unsigned byte array provide a non-resizable stream of the data. When using a byte array, you can neither append to nor shrink the stream, although you might be able to modify the existing contents depending on the parameters passed into the constructor. Empty memory streams are resizable, and can be written to and read from.

If a MemoryStream object is added to a ResX file or a .resources file, call the GetStream method at runtime to retrieve it.

If a MemoryStream object is serialized to a resource file it will actually be serialized as an UnmanagedMemoryStream. This behavior provides better performance, as well as the ability to get a pointer to the data directly, without having to go through Stream methods.

Platform Notes

Silverlight for Windows Phone

ArrayTypeMismatchException is not thrown when your application tries to store Stream.Null in a MemoryStream object.

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.

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