C# SendKey

MSDN SendKeys 類別
klcintw [C#]程式幫您按按鈕（SendKey & SendMessage）

MSDN SendInput
The SendInput function inserts the events in the INPUT structures serially into the keyboard or mouse input stream. These events are not interspersed with other keyboard or mouse input events inserted either by the user (with the keyboard or mouse) or by calls to keybd_event, mouse_event, or other calls to SendInput.