Unicode versions in .NET

Question

The documentation of CharUnicodeInfo.GetUnicodeCategory says:

Note that CharUnicodeInfo.GetUnicodeCategory does not always return the same UnicodeCategory value as the Char.GetUnicodeCategory method when passed a particular character as a parameter.

The CharUnicodeInfo.GetUnicodeCategory method is designed to reflect the current version of the Unicode standard. In contrast, although the Char.GetUnicodeCategory method usually reflects the current version of the Unicode standard, it might return a character's category based on a previous version of the standard, or it might return a category that differs from the current standard to preserve backward compatibility.

So, which version of the Unicode standard is reflected by CharUnicodeInfo.GetUnicodeCategory and Char.GetUnicodeCategory in which version of the .NET Framework?

Answer 1

This page has a wiki comment by Shawn Steele from microsoft, which I think should explain why using CharUnicodeInfo is preferred.

Answer 2

As far as I can tell, the unicode version isn't stored. The character lookup is implemented by storing the character info in an embedded resource called "charinfo.nlp" in mscorlib.dll, and this is used as a lookup table internally. There is a "version" property on the header to this lookup table data, but it is "0" in the binary data (offset 0x20), so I'm not sure what that's a version of, or if it's just not implemented.

Answer 3

As Michael Kaplan states:

The version released by The Unicode Consortium.

Because there really is no definitive answer to this very non-specific question. The answer always depends entirely on the [usually one] specific issue that the person asking is looking for the answer to

So the polite answer in the end is IT DEPENDS ON WHAT YOU MEAN. CAN YOU ELABORATE A BIT?

Answer 4

While I'M still looking for the Unicode version numbers that previous .NET Framework versions conform to, the documentation for the String class on MSDN states the Unicode version that the .NET Framework 4 conforms to:

In the .NET Framework 4, sorting, casing, normalization, and Unicode character information has been modified so that it is synchronized with Windows 7 and conforms to the Unicode 5.1 standard.