C#

List<FileInfo> fi = new List<FileInfo>();
ListBox l = new ListBox();
private void Form1_Load(object sender, EventArgs e)
{


}
private void GetSubFoldersAndFiles(string path)
{



    foreach (string d in Directory.GetDirectories(path))
    {
        try
        {
            GetSubFoldersAndFiles(d);
        }
        catch (Exception)
        {


        }

    }
    foreach (string f in Directory.GetFiles(path))
    {
        fi.Add(new FileInfo(f));

    }
}

private void Form1_Shown(object sender, EventArgs e)
{
    l.Dock = DockStyle.Fill;
    this.Controls.Add(l);


    foreach (DriveInfo di in DriveInfo.GetDrives())
    {
        if (di.IsReady)
        {
            GetSubFoldersAndFiles(di.RootDirectory.FullName);
        }
    }
    var a = (from s in fi orderby s.Length descending select s);
    l.DataSource = a.ToList();
}

<system.net>
<mailSettings>
<smtp from="validname@mydomain.com">
<network host="mail.mydomain.com" password="" userName="validname@mydomain.com"/>
</smtp>
</mailSettings>
</system.net>

DateTime dt1 = DateTime.ParseExact("11:15:00", "hh:mm:ss", new DateTimeFormatInfo());
DateTime dt2 = DateTime.ParseExact("11:20:00", "hh:mm:ss", new DateTimeFormatInfo());

TimeSpan ts1 = dt1.Subtract(dt2);
Console.WriteLine(ts1.ToString());

private DateTime started;

public Form1() {
    InitializeComponent();
    started=DateTime.Now;
    timer.Tick += new EventHandler(timer1_Tick);
    timer.Interval = (1000) * (1);
    timer.Start();
}

private void timer1_Tick(object sender, EventArgs e) {
    DateTime now=DateTime.Now;
    label6.Text = "It is now "+now.ToString("HH:mm:ss");
    double seconds=now.Subtract(started).TotalSeconds;
    label7.Text = "which is "+seconds+" seconds since this form started.";
}