Also.
From MainForm
mySecondForm frmSecondForm = new mySecondForm();
frmSecondForm.ShowDialog();
From Second Form
Timer formCloser = new Timer();
private void mySecondForm_Load(object sender, EventArgs e)
{
formCloser.Interval = 10000;
formCloser.Enabled = true;
frmCloser.Tick += new EventHandler(formClose_Tick)
}
private void formClose_Tick(object sender, EventArgs e)
{
this.DialogResult = DialogResult.OK;
}