に置いて置くとsend keyPCがハングしますForm_Shown()BreakpointForm_KeyDown()
 private void Form1_KeyDown(object sender, KeyEventArgs e)
 {           //breakpoint here
        if (e.KeyCode == Keys.A)
        {
            MessageBox.Show("caught");
        }
 }
 private void Form1_Shown(object sender, EventArgs e)
 {
        SendKeys.Send("A");
 }