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MemoryStream Class

Creates a stream whose backing store is memory.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)
[SerializableAttribute]
[ComVisibleAttribute(true)]
public class MemoryStream : Stream

The MemoryStream type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemoryStream()Initializes a new instance of the MemoryStream class with an expandable capacity initialized to zero.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemoryStream(Byte[])Initializes a new non-resizable instance of the MemoryStream class based on the specified byte array.
Public methodSupported by the XNA FrameworkMemoryStream(Int32)Initializes a new instance of the MemoryStream class with an expandable capacity initialized as specified.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemoryStream(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.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemoryStream(Byte[], Int32, Int32)Initializes a new non-resizable instance of the MemoryStream class based on the specified region (index) of a byte array.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemoryStream(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.
Public methodSupported by the XNA FrameworkMemoryStream(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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  NameDescription
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryCanReadGets a value indicating whether the current stream supports reading. (Overrides Stream.CanRead.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryCanSeekGets a value indicating whether the current stream supports seeking. (Overrides Stream.CanSeek.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryCanTimeoutGets a value that determines whether the current stream can time out. (Inherited from Stream.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryCanWriteGets a value indicating whether the current stream supports writing. (Overrides Stream.CanWrite.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryCapacityGets or sets the number of bytes allocated for this stream.
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryLengthGets the length of the stream in bytes. (Overrides Stream.Length.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryPositionGets or sets the current position within the stream. (Overrides Stream.Position.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryReadTimeoutGets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out. (Inherited from Stream.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibraryWriteTimeoutGets 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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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryBeginReadBegins an asynchronous read operation. (Inherited from Stream.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryBeginWriteBegins an asynchronous write operation. (Inherited from Stream.)
Public methodSupported by the XNA FrameworkCloseCloses the current stream and releases any resources (such as sockets and file handles) associated with the current stream. (Inherited from Stream.)
Public methodCopyTo(Stream)Reads the bytes from the current stream and writes them to the destination stream. (Inherited from Stream.)
Public methodCopyTo(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.)
Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Protected methodSupported by the XNA FrameworkCreateWaitHandle Obsolete. Allocates a WaitHandle object. (Inherited from Stream.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryDispose()Releases all resources used by the Stream. (Inherited from Stream.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryDispose(Boolean)Releases the unmanaged resources used by the MemoryStream class and optionally releases the managed resources. (Overrides Stream.Dispose(Boolean).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEndReadWaits for the pending asynchronous read to complete. (Inherited from Stream.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEndWriteEnds an asynchronous write operation. (Inherited from Stream.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryFlushOverrides Stream.Flush so that no action is performed. (Overrides Stream.Flush().)
Public methodSupported by the XNA FrameworkGetBufferReturns the array of unsigned bytes from which this stream was created.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeLifetimeServiceObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemberwiseClone()Creates a shallow copy of the current Object. (Inherited from Object.)
Protected methodMemberwiseClone(Boolean)Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
Protected methodObjectInvariantInfrastructure. Provides support for a Contract. (Overrides Stream.ObjectInvariant().)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryReadReads a block of bytes from the current stream and writes the data to a buffer. (Overrides Stream.Read(Byte[], Int32, Int32).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryReadByteReads a byte from the current stream. (Overrides Stream.ReadByte().)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySeekSets the position within the current stream to the specified value. (Overrides Stream.Seek(Int64, SeekOrigin).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySetLengthSets the length of the current stream to the specified value. (Overrides Stream.SetLength(Int64).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToArrayWrites the stream contents to a byte array, regardless of the Position property.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryWriteWrites a block of bytes to the current stream using data read from a buffer. (Overrides Stream.Write(Byte[], Int32, Int32).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryWriteByteWrites a byte to the current stream at the current position. (Overrides Stream.WriteByte(Byte).)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryWriteToWrites the entire contents of this memory stream to another stream.
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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.

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


using System;
using System.IO;
using System.Text;

class MemStream
{
    static void Main()
    {
        int count;
        byte[] byteArray;
        char[] charArray;
        UnicodeEncoding uniEncoding = new UnicodeEncoding();

        // Create the data to write to the stream.
        byte[] firstString = uniEncoding.GetBytes(
            "Invalid file path characters are: ");
        byte[] secondString = uniEncoding.GetBytes(
            Path.GetInvalidPathChars());

        using(MemoryStream memStream = new MemoryStream(100))
        {
            // 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++]);
            }

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

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

            // Read the first 20 bytes from the stream.
            byteArray = new byte[memStream.Length];
            count = memStream.Read(byteArray, 0, 20);

            // Read the remaining bytes, byte by byte.
            while(count < memStream.Length)
            {
                byteArray[count++] =
                    Convert.ToByte(memStream.ReadByte());
            }

            // 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);
        }
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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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