C#

public class MainForm : System.Windows.Forms.Form
{
    // left out

    public void DirSearch(string path)
    {
        try
        {
            foreach(string file in Directory.GetFiles(path))
            {
                Original original = new Original(new FileInfo(file));
                original.CheckDirectory(new DirectoryInfo(path));

                if(original.HasDuplicates())
                {
                    listViewResult.Items.Add(file);

                    foreach(string duplicate in original.GetDuplicates())
                    {
                        listViewResult.Items.Add(duplicate);
                    }
                }
            }
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
}

public class Duplicate
{
    private FileInfo _info;

    public Duplicate(FileInfo info)
    {
        this._info = info;
    }

    public bool IsDuplicate(FileInfo info)
    {
        return (_info.Name == info.Name) &&
            (_info.Length == info.Length) &&
            (_info.LastWriteTime == info.LastWriteTime) &&
            (_info.DirectoryName != info.DirectoryName);
    }
}

public class Original : Duplicate
{
    private ArrayList _list = new ArrayList();

    public Original(FileInfo info) : base(info) {}

    public void CheckFile(FileInfo info)
    {
        if(base.IsDuplicate(info))
        {
            this._list.Add(info.FullName);
        }
    }

    public void CheckDirectory(DirectoryInfo dirInfo)
    {
        foreach(FileInfo fileInfo in dirInfo.GetFiles())
        {
            CheckFile(fileInfo);
        }

        foreach(DirectoryInfo subDirInfo in dirInfo.GetDirectories())
        {
            CheckDirectory(subDirInfo);
        }
    }

    public IList GetDuplicates()
    {
        return this._list;
    }

    public bool HasDuplicates()
    {
        return (this._list.Count > 0);
    }
}

'John' , 'Joe' , 'Al''ex' , 'Philip' , 'Ja,coup' , 'Dan'

'John'
'Joe'
'Al''ex'
'Philip'
'Ja,coup'
'Dan'