国际化字符串比较的问题

摘自 Larry Osterman 的 blog 。

http://blogs.msdn.com/larryosterman/archive/2004/07/01/171078.aspx

一.  两个长度不一样的字符串有可能是相等的。

二.  将字符串转换成大写（或小写）的时候，转换后的字符串有可能长度会增加。

The first problem occurs in the very first line of the routine:

                  if (string1.Length != string2.Length)

The problem is that two strings can be equal, even if their lengths aren’t equal!  

My favorite example of this is the German sharp-s character, which is used in the German word straße.  The length of straße is 6 characters, and the length of the upper case form of the word (STRASSE) is 7 characters.  These strings are considered as equal in German, even though the lengths don’t match.