char type in C# is just UTF-16 code unit

[杨敏]

char type in C# is just UTF-16 code unit.
Unicode is not only 2^16(65536) characters, but 0x10ffff characters which called unicode code point.
see MSDN(http://msdn.microsoft.com/zh-cn/library/system.char(v=vs.110).aspx) and UTF-8 Everywhere(http://www.utf8everywhere.org/).