MemoryStream Class

 

Creates a stream whose backing store is memory.

To browse the .NET Framework source code for this type, see the Reference Source.

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

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

<SerializableAttribute>
<ComVisibleAttribute(True)>
Public Class MemoryStream
	Inherits Stream

NameDescription
System_CAPS_pubmethodMemoryStream()

Initializes a new instance of the MemoryStream class with an expandable capacity initialized to zero.

System_CAPS_pubmethodMemoryStream(Byte())

Initializes a new non-resizable instance of the MemoryStream class based on the specified byte array.

System_CAPS_pubmethodMemoryStream(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.

System_CAPS_pubmethodMemoryStream(Byte(), Int32, Int32)

Initializes a new non-resizable instance of the MemoryStream class based on the specified region (index) of a byte array.

System_CAPS_pubmethodMemoryStream(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.

System_CAPS_pubmethodMemoryStream(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.

System_CAPS_pubmethodMemoryStream(Int32)

Initializes a new instance of the MemoryStream class with an expandable capacity initialized as specified.

NameDescription
System_CAPS_pubpropertyCanRead

Gets a value indicating whether the current stream supports reading.(Overrides Stream.CanRead.)

System_CAPS_pubpropertyCanSeek

Gets a value indicating whether the current stream supports seeking.(Overrides Stream.CanSeek.)

System_CAPS_pubpropertyCanTimeout

Gets a value that determines whether the current stream can time out.(Inherited from Stream.)

System_CAPS_pubpropertyCanWrite

Gets a value indicating whether the current stream supports writing.(Overrides Stream.CanWrite.)

System_CAPS_pubpropertyCapacity

Gets or sets the number of bytes allocated for this stream.

System_CAPS_pubpropertyLength

Gets the length of the stream in bytes.(Overrides Stream.Length.)

System_CAPS_pubpropertyPosition

Gets or sets the current position within the stream.(Overrides Stream.Position.)

System_CAPS_pubpropertyReadTimeout

Gets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out. (Inherited from Stream.)

System_CAPS_pubpropertyWriteTimeout

Gets or sets a value, in miliseconds, that determines how long the stream will attempt to write before timing out. (Inherited from Stream.)

NameDescription
System_CAPS_pubmethodBeginRead(Byte(), Int32, Int32, AsyncCallback, Object)

Begins an asynchronous read operation. (Consider using ReadAsync instead; see the Remarks section.)(Inherited from Stream.)

System_CAPS_pubmethodBeginWrite(Byte(), Int32, Int32, AsyncCallback, Object)

Begins an asynchronous write operation. (Consider using WriteAsync instead; see the Remarks section.)(Inherited from Stream.)

System_CAPS_pubmethodClose()

Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. Instead of calling this method, ensure that the stream is properly disposed.(Inherited from Stream.)

System_CAPS_pubmethodCopyTo(Stream)

Reads the bytes from the current stream and writes them to another stream.(Inherited from Stream.)

System_CAPS_pubmethodCopyTo(Stream, Int32)

Reads the bytes from the current stream and writes them to another stream, using a specified buffer size.(Inherited from Stream.)

System_CAPS_pubmethodCopyToAsync(Stream)

Asynchronously reads the bytes from the current stream and writes them to another stream.(Inherited from Stream.)

System_CAPS_pubmethodCopyToAsync(Stream, Int32)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size.(Inherited from Stream.)

System_CAPS_pubmethodCopyToAsync(Stream, Int32, CancellationToken)

Asynchronously reads all the bytes from the current stream and writes them to another stream, using a specified buffer size and cancellation token.(Overrides Stream.CopyToAsync(Stream, Int32, CancellationToken).)

System_CAPS_pubmethodCreateObjRef(Type)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodCreateWaitHandle()

Obsolete.Allocates a WaitHandle object.(Inherited from Stream.)

System_CAPS_pubmethodDispose()

Releases all resources used by the Stream.(Inherited from Stream.)

System_CAPS_protmethodDispose(Boolean)

Releases the unmanaged resources used by the MemoryStream class and optionally releases the managed resources.(Overrides Stream.Dispose(Boolean).)

System_CAPS_pubmethodEndRead(IAsyncResult)

Waits for the pending asynchronous read to complete. (Consider using ReadAsync instead; see the Remarks section.)(Inherited from Stream.)

System_CAPS_pubmethodEndWrite(IAsyncResult)

Ends an asynchronous write operation. (Consider using WriteAsync instead; see the Remarks section.)(Inherited from Stream.)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodFlush()

Overrides the Stream.Flush method so that no action is performed.(Overrides Stream.Flush().)

System_CAPS_pubmethodFlushAsync()

Asynchronously clears all buffers for this stream and causes any buffered data to be written to the underlying device.(Inherited from Stream.)

System_CAPS_pubmethodFlushAsync(CancellationToken)

Asynchronously clears all buffers for this stream, and monitors cancellation requests.(Overrides Stream.FlushAsync(CancellationToken).)

System_CAPS_pubmethodGetBuffer()

Returns the array of unsigned bytes from which this stream was created.

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetLifetimeService()

Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodInitializeLifetimeService()

Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodObjectInvariant()

Obsolete. This API supports the product infrastructure and is not intended to be used directly from your code. Provides support for a Contract.(Inherited from Stream.)

System_CAPS_pubmethodRead(Byte(), Int32, Int32)

Reads a block of bytes from the current stream and writes the data to a buffer.(Overrides Stream.Read(Byte(), Int32, Int32).)

System_CAPS_pubmethodReadAsync(Byte(), Int32, Int32)

Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.(Inherited from Stream.)

System_CAPS_pubmethodReadAsync(Byte(), Int32, Int32, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.(Overrides Stream.ReadAsync(Byte(), Int32, Int32, CancellationToken).)

System_CAPS_pubmethodReadByte()

Reads a byte from the current stream.(Overrides Stream.ReadByte().)

System_CAPS_pubmethodSeek(Int64, SeekOrigin)

Sets the position within the current stream to the specified value.(Overrides Stream.Seek(Int64, SeekOrigin).)

System_CAPS_pubmethodSetLength(Int64)

Sets the length of the current stream to the specified value.(Overrides Stream.SetLength(Int64).)

System_CAPS_pubmethodToArray()

Writes the stream contents to a byte array, regardless of the Position property.

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubmethodTryGetBuffer(ArraySegment(Of Byte))

Returns the array of unsigned bytes from which this stream was created. The return value indicates whether the conversion succeeded.

System_CAPS_pubmethodWrite(Byte(), Int32, Int32)

Writes a block of bytes to the current stream using data read from a buffer.(Overrides Stream.Write(Byte(), Int32, Int32).)

System_CAPS_pubmethodWriteAsync(Byte(), Int32, Int32)

Asynchronously writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.(Inherited from Stream.)

System_CAPS_pubmethodWriteAsync(Byte(), Int32, Int32, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.(Overrides Stream.WriteAsync(Byte(), Int32, Int32, CancellationToken).)

System_CAPS_pubmethodWriteByte(Byte)

Writes a byte to the current stream at the current position.(Overrides Stream.WriteByte(Byte).)

System_CAPS_pubmethodWriteTo(Stream)

Writes the entire contents of this memory stream to another stream.

System_CAPS_noteNote

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.

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.

System_CAPS_importantImportant

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.

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.

The following code example shows how to read and write data using memory as a backing store.

Imports System
Imports System.IO
Imports System.Text

Module MemStream

    Sub Main()

        Dim count As Integer
        Dim byteArray As Byte()
        Dim charArray As Char()
        Dim uniEncoding As New UnicodeEncoding()

        ' Create the data to write to the stream.
        Dim firstString As Byte() = _
            uniEncoding.GetBytes("Invalid file path characters are: ")
        Dim secondString As Byte() = _
            uniEncoding.GetBytes(Path.GetInvalidPathChars())

        Dim memStream As New MemoryStream(100)
        Try
            ' Write the first string to the stream.
            memStream.Write(firstString, 0 , firstString.Length)

            ' Write the second string to the stream, byte by byte.
            count = 0
            While(count < secondString.Length)
                memStream.WriteByte(secondString(count))
                count += 1
            End While

            ' Write the stream properties to the console.
            Console.WriteLine( _
                "Capacity = {0}, Length = {1}, Position = {2}", _
                memStream.Capacity.ToString(), _
                memStream.Length.ToString(), _
                memStream.Position.ToString())

            ' Set the stream position to the beginning of the stream.
            memStream.Seek(0, SeekOrigin.Begin)

            ' Read the first 20 bytes from the stream.
            byteArray = _
                New Byte(CType(memStream.Length, Integer)){}
            count = memStream.Read(byteArray, 0, 20)

            ' Read the remaining Bytes, Byte by Byte.
            While(count < memStream.Length)
                byteArray(count) = _
                    Convert.ToByte(memStream.ReadByte())
                count += 1
            End While

            ' Decode the Byte array into a Char array 
            ' and write it to the console.
            charArray = _
                New Char(uniEncoding.GetCharCount( _
                byteArray, 0, count)){}
            uniEncoding.GetDecoder().GetChars( _
                byteArray, 0, count, charArray, 0)
            Console.WriteLine(charArray)
        Finally
            memStream.Close()
        End Try

    End Sub
End Module

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

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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