private void textBox1_keypress(object sender, KeyPressEventArgs k)
{
k.Handled = true;
if ((k.KeyChar >= '0' && k.KeyChar <= '9') ||
k.KeyChar == '\t' ||
k.KeyChar == '\b' ||
k.KeyChar == '\r')
{
k.Handled = false;
}
if (k.KeyChar == '\r')
{
monthCalendar1.Focus();
}
}