Это отстой, но вам придется написать собственный класс .NET StreamAdapter. К счастью, вы можете украсть весь код от Microsoft:
public class StreamAdapter : System.Runtime.InteropServices.ComTypes.IStream
{
// Fields
protected Stream dataStream;
private long virtualPosition = -1L;
// Methods
internal StreamAdapter(Stream stream)
{
if (!stream.CanSeek)
{
int num;
byte[] sourceArray = new byte[0x100];
int offset = 0;
do
{
if (sourceArray.Length < (offset + 0x100))
{
byte[] destinationArray = new byte[sourceArray.Length * 2];
Array.Copy(sourceArray, destinationArray, sourceArray.Length);
sourceArray = destinationArray;
}
num = stream.Read(sourceArray, offset, 0x100);
offset += num;
}
while (num != 0);
this.dataStream = new MemoryStream(sourceArray);
}
else
{
this.dataStream = stream;
}
}
private void ActualizeVirtualPosition()
{
if (this.virtualPosition != -1L)
{
if (this.virtualPosition > this.dataStream.Length)
{
this.dataStream.SetLength(this.virtualPosition);
}
this.dataStream.Position = this.virtualPosition;
this.virtualPosition = -1L;
}
}
public virtual System.Runtime.InteropServices.ComTypes.IStream Clone()
{
NotImplemented();
return null;
}
public virtual void Commit(int grfCommitFlags)
{
this.dataStream.Flush();
this.ActualizeVirtualPosition();
}
[SecurityPermission(SecurityAction.Assert, Flags=SecurityPermissionFlag.UnmanagedCode), UIPermission(SecurityAction.Demand, Window=UIPermissionWindow.AllWindows)]
public virtual long CopyTo(UnsafeNativeMethods.IStream pstm, long cb, long[] pcbRead)
{
int num = 0x1000;
IntPtr buf = Marshal.AllocHGlobal(num);
if (buf == IntPtr.Zero)
{
throw new OutOfMemoryException();
}
long num2 = 0L;
try
{
while (num2 < cb)
{
int length = num;
if ((num2 + length) > cb)
{
length = (int) (cb - num2);
}
int len = this.Read(buf, length);
if (len == 0)
{
goto Label_006C;
}
if (pstm.Write(buf, len) != len)
{
throw EFail("Wrote an incorrect number of bytes");
}
num2 += len;
}
}
finally
{
Marshal.FreeHGlobal(buf);
}
Label_006C:
if ((pcbRead != null) && (pcbRead.Length > 0))
{
pcbRead[0] = num2;
}
return num2;
}
protected static ExternalException EFail(string msg)
{
throw new ExternalException(msg, -2147467259);
}
public virtual Stream GetDataStream()
{
return this.dataStream;
}
public virtual void LockRegion(long libOffset, long cb, int dwLockType)
{
}
protected static void NotImplemented()
{
throw new ExternalException(SR.GetString("NotImplemented"), -2147467263);
}
public virtual int Read(IntPtr buf, int length)
{
byte[] buffer = new byte[length];
int num = this.Read(buffer, length);
Marshal.Copy(buffer, 0, buf, length);
return num;
}
public virtual int Read(byte[] buffer, int length)
{
this.ActualizeVirtualPosition();
return this.dataStream.Read(buffer, 0, length);
}
public virtual void Revert()
{
NotImplemented();
}
public virtual long Seek(long offset, int origin)
{
long virtualPosition = this.virtualPosition;
if (this.virtualPosition == -1L)
{
virtualPosition = this.dataStream.Position;
}
long length = this.dataStream.Length;
switch (origin)
{
case 0:
if (offset > length)
{
this.virtualPosition = offset;
break;
}
this.dataStream.Position = offset;
this.virtualPosition = -1L;
break;
case 1:
if ((offset + virtualPosition) > length)
{
this.virtualPosition = offset + virtualPosition;
break;
}
this.dataStream.Position = virtualPosition + offset;
this.virtualPosition = -1L;
break;
case 2:
if (offset > 0L)
{
this.virtualPosition = length + offset;
break;
}
this.dataStream.Position = length + offset;
this.virtualPosition = -1L;
break;
}
if (this.virtualPosition != -1L)
{
return this.virtualPosition;
}
return this.dataStream.Position;
}
public virtual void SetSize(long value)
{
this.dataStream.SetLength(value);
}
public void Stat(IntPtr pstatstg, int grfStatFlag)
{
STATSTG structure = new STATSTG();
structure.cbSize = this.dataStream.Length;
Marshal.StructureToPtr(structure, pstatstg, true);
}
public virtual void UnlockRegion(long libOffset, long cb, int dwLockType)
{
}
public virtual int Write(IntPtr buf, int length)
{
byte[] destination = new byte[length];
Marshal.Copy(buf, destination, 0, length);
return this.Write(destination, length);
}
public virtual int Write(byte[] buffer, int length)
{
this.ActualizeVirtualPosition();
this.dataStream.Write(buffer, 0, length);
return length;
}
// Nested Types
[StructLayout(LayoutKind.Sequential)]
public class STATSTG
{
public IntPtr pwcsName = IntPtr.Zero;
public int type;
[MarshalAs(UnmanagedType.I8)]
public long cbSize;
[MarshalAs(UnmanagedType.I8)]
public long mtime;
[MarshalAs(UnmanagedType.I8)]
public long ctime;
[MarshalAs(UnmanagedType.I8)]
public long atime;
[MarshalAs(UnmanagedType.I4)]
public int grfMode;
[MarshalAs(UnmanagedType.I4)]
public int grfLocksSupported;
public int clsid_data1;
[MarshalAs(UnmanagedType.I2)]
public short clsid_data2;
[MarshalAs(UnmanagedType.I2)]
public short clsid_data3;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b0;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b1;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b2;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b3;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b4;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b5;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b6;
[MarshalAs(UnmanagedType.U1)]
public byte clsid_b7;
[MarshalAs(UnmanagedType.I4)]
public int grfStateBits;
[MarshalAs(UnmanagedType.I4)]
public int reserved;
}
}