How To Sort File Names In c#

Question

1.00/5 (2 votes)

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I want to get all files from a folder but files are not sorted.
The file' names are number for example 1,2,3,4,...,1000.
How to sort this file names?

C#

string[] fileNames = Directory.GetFiles("Spaceman");
Array.Sort(fileNames, StringComparer.InvariantCulture);
foreach (string files in fileNames)
{
    listBox2.Items.Add(files);
}

Posted 27-Feb-15 1:41am

Avenger1

Updated 27-Feb-15 1:51am

v3

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2 solutions

Solution 4

I think what the ~~other~~ first 2 posters have missed is that you explicitly said that the filenames are numeric.

So if you have filenames of

the solutions offered so far will present that list in the following order

I'm assuming you want the order as I originally presented it.
To do that you need to strip the path off the filenames and convert it to a number before sorting it. I'm continuing to use GetFiles as you have done because I think DirectoryInfo is a little heavyweight for what we want.

First I created a static function that will strip off the foldername and convert the filename to an integer (if possible)

C#

private static string formatFileNumberForSort(string inVal)
{
    int o;
    if (int.TryParse(Path.GetFileName(inVal), out o))
    {
        Console.WriteLine(string.Format("{0:0000000000}", o));
        return string.Format("{0:0000000000}", o);
    }
    else
        return inVal;
}

I then use that function like this

C#

var fileNames = Directory.GetFiles("Spaceman").OrderBy(formatFileNumberForSort);
foreach(var s in fileNames)
    Console.WriteLine("{0}", s);

which produces results of

Spaceman\1
Spaceman\2
Spaceman\10
Spaceman\11
Spaceman\20
Spaceman\21

As requested here is my entire code ... created a new Windows Forms application and stuck a button on the default form.

C#

using System;
using System.IO;
using System.Linq;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // I have files called 1, 2, 10, 11, 20, 21 in my temp\test2 folder
            var fileNames = Directory.GetFiles("c:\\temp\\test2").OrderBy(formatFileNumberForSort);
            foreach(var s in fileNames)
                Console.WriteLine("{0}", s);
        }

        private static string formatFileNumberForSort(string inVal)
        {
            int o;
            if (int.TryParse(Path.GetFileName(inVal), out o))
            {
                Console.WriteLine(string.Format("{0:0000000000}", o));
                return string.Format("{0:0000000000}", o);
            }
            else
                return inVal;
        }
    }
}

Posted 27-Feb-15 2:13am

CHill60

Updated 27-Feb-15 5:00am

v3

Comments

Avenger1 27-Feb-15 9:36am

it didn't work in vs 2013

CHill60 27-Feb-15 10:38am

I tested this in VS2013 - what do you mean by "didn't work" ?

Avenger1 27-Feb-15 9:48am

please see these 2 image of my program to see my problem, the first is for 100 image
http://upload7.ir/uploads//1af97ab4a609f7dc76b8dad42236f1ad2a9722d8.jpg

and this second link is for 1000 image
http://upload7.ir/uploads//27a25c8113166567aa0ef5ba5db522599e036cd0.jpg
i want it sort like this
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,...,1000

CHill60 27-Feb-15 10:40am

I've just tested my code again and it definitely produces the order correctly.

Avenger1 27-Feb-15 10:54am

so why for me its not working correct!
can you upload your project for me, please
With Respect

CHill60 27-Feb-15 11:01am

I've put all of the code into my solution - as you can see there is not a lot!

CHill60 27-Feb-15 11:11am

I've found out why it is not working for you ... you must have set the Sorted property on the ListBox to True (the default is false)

Avenger1 27-Feb-15 14:04pm

it is "true" but its not working
:(

CHill60 28-Feb-15 5:18am

It's needs to be false for this to work, the ListBox is changing the sort order

Avenger1 28-Feb-15 13:18pm

it answered but a little problem still in it, i want to show the numbers single then Double-digit and then three-digit of the top to down

CHill60 2-Mar-15 7:48am

In other words in numeric order! The code I've given does that (in a ListBox where Sorted = false)

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John C Rayan · Accepted Answer · 2015-02-27T01:52:00

I have tested this and works fine.

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;


namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {


        DirectoryInfo info = new DirectoryInfo("c:\\Snowman");
        string[] fileNames = info.GetFiles().OrderBy(p => Path.GetFileNameWithoutExtension(p.Name),new ComparerN()  )
                                 .Select(fi => fi.Name).ToArray();




        }
    }


    public class ComparerN : IComparer<string>
    {
        public int Compare(string sf, string ss)
        {
            if (IsNumer(sf) && IsNumer(ss))
            {
                if (Convert.ToInt32(sf) > Convert.ToInt32(ss))
                {
                    return 1;
                }
                if (Convert.ToInt32(sf) < Convert.ToInt32(ss))
                {
                    return -1;
                }
                if (Convert.ToInt32(sf) == Convert.ToInt32(ss))
                {
                    return 0;
                }
            }

            if (IsNumer(sf) && !IsNumer(ss))
                return -1;

            if (!IsNumer(sf) && IsNumer(ss))
                return 1;

            return string.Compare(sf, ss, true);
        }

        public static bool IsNumer(object v)
        {

            try
            {
                int it = Convert.ToInt32(v.ToString());
                return true;
            }
            catch (FormatException){return false;}
        }
    }

}