LibTiff.net isn't setting the Subject tag - tags

Question

I'm trying to mimic some production code to generate Tiffs with a subject for testing purposes (IE in windows, right click, go to properties and the details tab there is a subject). We place some text we need to reference later in the subject field. The field we use is 0x9c9f which as far as I can find is (Subject tag used by Windows, encoded in UCS2)
Here's the code I'm using to generate the tag
public static void TagExtender(Tiff tif)
{
TiffFieldInfo[] tiffFieldInfo =
{
new TiffFieldInfo(TIFFTAG_SUBJECT, 256, 256, TiffType.BYTE, FieldBit.Custom, true, false, "XPSubject"),
};
tif.MergeFieldInfo(tiffFieldInfo, tiffFieldInfo.Length);
//if (m_parentExtender != null)
// m_parentExtender(tif);
}
public static void GenerateTiff(string filename, int pages = 1, bool encrypt = false, string tag = null)
{
// Register the custom tag handler
if (m_parentExtender == null)
{
Tiff.TiffExtendProc extender = TagExtender;
m_parentExtender = Tiff.SetTagExtender(extender);
}
// Open the output image
using (Tiff output = Tiff.Open(filename, "w"))
{
//...other code to generate tiff
if (tag != null)
{
byte[] bytes = UnicodeStr2HexStr(tag);
output.SetField(TIFFTAG_SUBJECT, bytes.Length-1, bytes);
}
// Code to actually write the image ....
output.WriteDirectory();
}
output.Close();
}
Basically, the tag (code wise) appears to be in the tiff but the windows properties dialog never shows it. Anything special needed to get this in place?

Answer 1

You are passing a bytecount, but set the passCount flag to false.
If you want to pass the count, use these lines at their correct positions:
// Your FieldInfo
new TiffFieldInfo((TiffTag)40095, -1, -1, TiffType.BYTE, FieldBit.Custom, true, true, "XPSubject")
// Your Input
byte[] test = Encoding.Unicode.GetBytes("Test3");
tiff.SetField((TiffTag)40095, test.Length, test);