How keystroke simulated in RPA Tools like Automation Anywhere

Question

I'm curious to know how Top RPA tools like AA and UiPath simulate keystroke to the applications. I've built an application with use of Keybd_event to simulate keystrokes but I keep facing the issue of scan code parameter of keybd_event - as it required to perform keystroke in Citrix environment.

private void PressKeyVK(int eKeys, bool bHoldKeydown, bool bRelease) { int lScan, lExtended; lScan = MapVirtualKey(eKeys, 1); lExtended = 0; if (lScan == 0) lExtended = (int)KeyBoardEventEnums.KEYEVENTF_EXTENDEDKEY; lScan = MapVirtualKey(eKeys, 0); if (!bRelease) keybd_event((byte)eKeys, (byte)lScan, (uint)lExtended, UIntPtr.Zero); if (!bHoldKeydown) keybd_event((byte)eKeys, (byte)lScan, (uint)KeyBoardEventEnums.KEYEVENTF_KEYUP | (uint)lExtended, UIntPtr.Zero); }

Answer 1

RPA is such a versatile tool, it uses different technology for a different layer. 

 For Local machines, it uses sendmessage and postmessage APIs. For thin layer applications such as RDP and Citrix, it simulates software keypress similar to application.sendkeys