You can try this class I wrote, that provides a System.IO.Stream adapter over the MgByteReader:
Thank you Jackie,
when I add your class to my project, I found I cannot reference the namespace OSGeo.MapGuide.Viewer; And Line 216 "Strings" not exist in the context. I am pretty new, can you help me more? Thanks again.
That file can't just be dropped in, so change/rename the namespace
Strings.ErrorStreamNotRewindable is just a localizable message, just replace it with something equivalent