C# highest string

Question

This seems so trivial but I'm not finding an answer with Google.

I'm after a high value for a string for a semaphore at the end of a sorted list of strings.

It seems to me that char.highest.ToString() should do it--but this compares low, not high.

Obviously it's not truly possible to create a highest possible string because it would always be lower than the same thing + more data but the strings I'm sorting are all valid pathnames and thus the symbols used are constrained.

In response to the comments:

In the pre-unicode days in Delphi I would simply have used #255. I simply want a string that will compare higher than any possible pathname. This should be trivial--why isn't it??

Response #2:

It's not the sorting that requires the sentinel, it's the processing afterwards. I have multiple lists that I am sort-of merging (a simplistic merge won't do the job.) and either I duplicate code or I have dummy values that always compare high.

Answer 1

A string representation of the highest character will only be one character long.

Why don't you just append it as a semaphore after sorting, rather than trying to make it something that will sort afterwards?

Alternatively, you could specify your own comparator that sorts your token after any other string, and calls the default comparator otherwise.

Answer 2

Something like this?

public static String Highest(this String value)
{
    Char highest = '\0';
    foreach (Char c in value)
    {
        highest = Math.Max(c, highest); 
    }
    return new String(new Char[] { highest });
}