多螢幕環境下，指定螢幕顯示畫面 (C#)

private void ChangeScreen(Form aForm, int screenId)  
{   
  // 先將 Form 設定為 Normal   
  aForm.WindowState = FormWindowState.Normal;   
  
  // 改 Location   
  aForm.StartPosition = FormStartPosition.Manual;   
  if (screenId < Screen.AllScreens.Length)   
  {   
    aForm.Location = Screen.AllScreens[screenId].WorkingArea.Location;   
  }   
  
  // 最後設定成 Maximized   
  aForm.WindowState = FormWindowState.Maximized;   
}