IStream Interface


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Provides the managed definition of the IStream interface, with ISequentialStream functionality.

Namespace:   System.Runtime.InteropServices.ComTypes
Assembly:  mscorlib (in mscorlib.dll)

public interface IStream


Creates a new stream object with its own seek pointer that references the same bytes as the original stream.


Ensures that any changes made to a stream object that is open in transacted mode are reflected in the parent storage.

System_CAPS_pubmethodCopyTo(IStream, Int64, IntPtr, IntPtr)

Copies a specified number of bytes from the current seek pointer in the stream to the current seek pointer in another stream.

System_CAPS_pubmethodLockRegion(Int64, Int64, Int32)

Restricts access to a specified range of bytes in the stream.

System_CAPS_pubmethodRead(Byte[], Int32, IntPtr)

Reads a specified number of bytes from the stream object into memory starting at the current seek pointer.


Discards all changes that have been made to a transacted stream since the last Commit call.

System_CAPS_pubmethodSeek(Int64, Int32, IntPtr)

Changes the seek pointer to a new location relative to the beginning of the stream, to the end of the stream, or to the current seek pointer.


Changes the size of the stream object.

System_CAPS_pubmethodStat(STATSTG, Int32)

Retrieves the STATSTG structure for this stream.

System_CAPS_pubmethodUnlockRegion(Int64, Int64, Int32)

Removes the access restriction on a range of bytes previously restricted with the LockRegion method.

System_CAPS_pubmethodWrite(Byte[], Int32, IntPtr)

Writes a specified number of bytes into the stream object starting at the current seek pointer.

For more information, see the documentation for the IStream and ISequentialStream interfaces in the MSDN Library.

The common language runtime throws an exception when a COM method in native code returns an HRESULT other than S_OK. For more information, see How to: Map HRESULTs and Exceptions.

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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