You can wrap the IStream in a .NET wrapper which .NET objects can the
access, like this:
using System;
using System.IO;
using System.Runtime.InteropServices;
public class ComStream : Stream {
// the managed stream being wrapped
UCOMIStream originalStream_;
public ComStream( UCOMIStream stream ) {
if( stream != null ) {
originalStream_ = stream;
}
else {
throw new ArgumentNullException( "stream" );
}
}
~ComStream() {
Close();
}
// property to get original stream object
public UCOMIStream UnderlyingStream {
get {
return originalStream_;
}
}
// reads a specified number of bytes from the stream object
// into memory starting at the current seek pointer
public unsafe override int Read( byte[] buffer, int offset, int count ) {
if( originalStream_ == null ) {
throw new ObjectDisposedException( "originalStream_" );
}
if( offset != 0 ) {
throw new NotSupportedException("only 0 offset is supported");
}
int bytesRead;
IntPtr address = new IntPtr( &bytesRead );
originalStream_.Read( buffer, count, address );
return bytesRead;
}
// writes a specified number of bytes into the stream object
// starting at the current seek pointer
public override void Write( byte[] buffer, int offset, int count ) {
if( originalStream_ == null ) {
throw new ObjectDisposedException( "originalStream_" );
}
if( offset != 0 ) {
throw new NotSupportedException("only 0 offset is supported");
}
originalStream_.Write( buffer, count, IntPtr.Zero );
}
// changes the seek pointer to a new location relative to the beginning
// of the stream, the end of the stream, or the current seek position
public unsafe override long Seek( long offset, SeekOrigin origin ){
if( originalStream_ == null ) {
throw new ObjectDisposedException( "originalStream_" );
}
long position = 0;
IntPtr address = new IntPtr( &position );
originalStream_.Seek( offset, (int) origin, address );
return position;
}
public override long Length {
get {
if( originalStream_ == null ) {
throw new ObjectDisposedException( "originalStream_" );
}
STATSTG statstg;
originalStream_.Stat( out statstg, 1 /* STATSFLAG_NONAME*/ );
return statstg.cbSize;
}
}
public override long Position {
get { return Seek( 0, SeekOrigin.Current ) ; }
set { Seek( value, SeekOrigin.Begin ) ; }
}
// changes the size of the stream object
public override void SetLength( long value ) {
if( originalStream_ == null ) {
throw new ObjectDisposedException( "originalStream_" );
}
originalStream_.SetSize( value );
}
// closes (disposes) the stream
public override void Close() {
if( originalStream_ != null ) {
originalStream_.Commit( 0 );
// Marshal.ReleaseComObject( originalStream_ );
originalStream_= null;
GC.SuppressFinalize( this );
}
}
public override void Flush() {
originalStream_.Commit(0);
}
public override bool CanRead {
get { return true ; }
}
public override bool CanWrite {
get { return true ;}
}
public override bool CanSeek {
get { return true ; }
}
}
This comes mostly from this book:
http://www.amazon.com/exec/obidos/t...=sr_8_4/102-1502892-3914561?v=glance&n=507846
Klaus H. Probst said:
I don't think you can just plain convert it, but you can always read the
contents of one into another.
