C#

If you are using SessionEnding in a Windows form to detect a system logoff or reboot,
there is no deterministic way to decide whether the
System.Windows.Forms.Form.Closing event will fire before this event.

If you want to perform some special tasks before System.Windows.Forms.Form.Closing is fired,
you need to ensure that SessionEnding fires before System.Windows.Forms.Form.Closing.
To do this, you need to trap the WM_QUERYENDSESSION in the form by
overriding the WndProc function. The following example demonstrates
how to do this in a deterministic way,

Label label = null;
System.Windows.Forms.Control.ControlCollection cc = this.Controls;
if(cc != null)
{
    foreach(Control c in cc)
    {
        if(c is System.Windows.Forms.Label)
        {
            label = (Label)c;
            label.Text = "Nick";
        }

    }
}

private void bClick(object sender, EventArgs e)
{
	ProcessStartInfo pi = new ProcessStartInfo("mailto:you@here.com");
	Process.Start(pi);
}