Converting graphics with ExportString

Can ExportString export an EMF or GIF? In this demo streamoutput.emf somehow gets mangled:

Quiet[DeleteFile["C:\\Temp\\thisworks.emf"]];
Quiet[DeleteFile["C:\\Temp\\streamoutput.emf"]];

graphic = Graphics[{Thick, Red, Circle[{#, 0}] & /@ Range[4],
    Black, Dashed, Line[{{0, 0}, {5, 0}}]}];
Export["C:\\Temp\\thisworks.emf", graphic, "EMF"];

file = ExportString[graphic, "EMF"];
stream = OpenWrite["C:\\Temp\\streamoutput.emf", BinaryFormat -> True];
Write[stream, file];
Close[stream];

If ExportString worked I might be able to use it to transfer EMFs through NETLink, e.g.

kernel.Compute("ExportString[Graphics[Rectangle[]], \"EMF\"]");
File.WriteAllText("C:\\Temp\\output.emf", kernel.Result.ToString());

Addendum

Got开发者_如何学C that working.

kernel.Compute("ExportString[Graphics[Rectangle[]],{\"Base64\",\"EMF\"}]");
byte[] decodedBytes = Convert.FromBase64String(kernel.Result.ToString());
File.WriteAllBytes("C:\\Temp\\output.emf", decodedBytes);

By the looks of it, Write includes the quotation marks of the string file when writing to stream, so the output file starts with something like "GIF.... instead of just GIF.... When using BinaryWrite instead of Write it does seem to work. For example

file = ExportString[graphic, "GIF"];
stream = OpenWrite["streamoutput.gif", BinaryFormat -> True];
BinaryWrite[stream, file];
Close[stream];
Import["streamoutput.gif"]

produces

So ExportString does produce a valid string for GIF at least. I don't have windows so I can't test for EMF.