How to find duplicates?

[TheDarklord]

I have some code which searches through directories and folders for mp3 files and then displays them to the list boxes.

foreach (string foldername in Directory.GetDirectories(DirectoryName))
            {
                MP3Header mp3hdr = new MP3Header();
                string Mp3Filename;



                foreach (string filename in Directory.GetFiles(foldername))
                {
                    string extension = Path.GetExtension(filename);
                    FileInfo f = new FileInfo(filename);


                    if (extension == FileTypeExtension)
                    {
                        this.listBox1.Items.Add(filename);
                    }


                    if (f.Length <= thisFileLength)
                    {
                        this.listBox2.Items.Add(filename);

                    }

                    // Form1 tag = new Form1();

                    bool boolIsMP3 = mp3hdr.ReadMP3Information(filename);

                    this.listBoxFileName.Items.Add(mp3hdr.strFileName);
                    this.listBox3.Items.Add(mp3hdr.lngFileSize.ToString());
                    this.listBoxBitRate.Items.Add(mp3hdr.intBitRate.ToString());
                    this.listBoxFrequency.Items.Add(mp3hdr.intFrequency.ToString());
                    this.listBoxstrMode.Items.Add(mp3hdr.strMode);
                    this.listBoxstrLength.Items.Add(mp3hdr.strLengthFormatted);

                    //Mp3Filename = filename;

                    Filelist.Add(mp3hdr.strFileName);

                    this.listBox4.Items.Add(Filelist);
}

How can I edit it so that it finds files which are the same as one another?

For example if one file in one folder has the same name as another file in another folder?

foreach (FileName in Filelist)
            {
                if (filename == mp3hdr.strFileName)
                {
                    this.listBox4.Items.Add(filename);
                }
            }

Something along those lines?

[mariocatch]

You've created this same thread 3 times on this forum. Stop.