Sorting directory files and getting the highest file name

Question

I have a directory with 40 files with names from 0 to 39 (for example), I am trying to get the file with the largest number in its name (which means I need to get \"39\") I

Answer 1

There is a native function in windows StrCmpLogicalW that will compare in strings numbers as numbers instead of letters. It is easy to make a comparer that calls out to that function and uses it for it's comparisons.

public class StrCmpLogicalComparer : Comparer
{
    [DllImport("Shlwapi.dll", CharSet = CharSet.Unicode)]
    private static extern int StrCmpLogicalW(string x, string y);

    public override int Compare(string x, string y)
    {
        return StrCmpLogicalW(x, y);
    }
}

Here is a example program that will show the diffrence between the default sort and the StrCmpLogicalW sort

class Program
{
    static void Main()
    {
        List items = new List()
        {
            "Example1.txt", "Example2.txt", "Example3.txt", "Example4.txt", "Example5.txt", "Example6.txt", "Example7.txt", "Example8.txt", "Example9.txt", "Example10.txt",
            "Example11.txt", "Example12.txt", "Example13.txt", "Example14.txt", "Example15.txt", "Example16.txt", "Example17.txt", "Example18.txt", "Example19.txt", "Example20.txt"
        };

        items.Sort();

        foreach (var item in items)
        {
            Console.WriteLine(item);
        }

        Console.WriteLine();

        items.Sort(new StrCmpLogicalComparer());

        foreach (var item in items)
        {
            Console.WriteLine(item);
        }
        Console.ReadLine();
    }
}

which outputs

Example1.txt
Example10.txt
Example11.txt
Example12.txt
Example13.txt
Example14.txt
Example15.txt
Example16.txt
Example17.txt
Example18.txt
Example19.txt
Example2.txt
Example20.txt
Example3.txt
Example4.txt
Example5.txt
Example6.txt
Example7.txt
Example8.txt
Example9.txt

Example1.txt
Example2.txt
Example3.txt
Example4.txt
Example5.txt
Example6.txt
Example7.txt
Example8.txt
Example9.txt
Example10.txt
Example11.txt
Example12.txt
Example13.txt
Example14.txt
Example15.txt
Example16.txt
Example17.txt
Example18.txt
Example19.txt
Example20.txt