Api to catch kestrokes

[markandeya]

I need to catch keyboard input so i can then send information codes to programs so a Sanskrit font will be typed. We will programatically catch up to three keys for 1 sanskrit char, one key flagging tht there is a 3 key code coming. How to do through the Api as the catch must be in the backround while a word processing or page formating program is running as the active window. Tnakh you for your help and suggestions. [email protected]

[MerrionComputin]

If you are running Windows NT/2000/XP you can install a WH_KEYBOARD_LL hook with the SetWindowsHook API call.

HTH,
Duncan

[ChiefRB]

Just a query duncan - will that set a global hook? I've read in many places that VB cannot set a global hook, but I'm still curious. I need to be told from a reputable API source... you.

[MerrionComputin]

Generally speaking you can't implement a system wide hook in Visual basic, because you can't get an activeX dll injected into another application - you need a dll with an exports table for that...
However some global hooks occur in the operating system layer, specifically WH_KEYBOARD_LL, WH_MOUSE_LL and WH_JOURNALRECORD so they don't suffer from this restriction.

You can implement a global keyboard hook using the EventVB.dll thus:
(The syntax is a bit ugly - it's a work in progress...)

'\\ Form declarations
Private WithEvents apiLink As EventVB.ApiFunctions
Private WithEvents hook As EventVB.EnumHandler 
 
'\\ Form load
Private Sub Form_Load()
  Set apiLink = New EventVb.ApiFunctions
  Set hook = apiLink.EventHandlerLink
 
  hook.StartHook WH_KEYBOARD_LL,apiLink.AppModuleHandle, 0
 
End Sub
 
'\\ Form unload
Private Sub Form_Unload(Cancel As Integer)
   hook.StopHook WH_KEYBOARD_LL
End Sub
 
Private Sub hook_HOOKPROCKEYBOARDLL(Action As EventVB.enHookCode, ByVal KeyState As Long, ByVal KeyStrokeInfo As EventVB.ApiKBDLLHOOKSTRUCT, lMsgRet As Long)
 
'\\ Tp prevent a message being passed on to the application,
'\\ set lMsgRet = 1
 
End Sub

HTH,
Duncan

[MerrionComputin]

because you can't get an activeX dll injected into another application

Note that I am working on a way around this at the moment but it is proving very troublesome so it's not yet ready ...