vb6 suppress keyboard strokes with API? (making a hotkey) - vb6

Question

I've searched, and can't seem to find an answer, so any help would be appreciated.
I want to make a hotkey, but when the hotkey is pressed, I don't want the actual "character" to be displayed, just the action to be performed.
So for example, I have this:
Private Declare Function GetAsyncKeyState Lib "user32" _
(ByVal vKey As KeyCodeConstants) As Long
Private Const VK_A = &H41
Private Sub keyboardTimer001_Timer()
If KeyDown(VK_A) Then
' do my stuff, but DONT DISPLAY the letter "A"
End If
end sub
So this basically just has a timer (interval 1) checking the async keyboard. If it detects that the letter "a" was pressed, I perform an action. But I want it to do this WITHOUT printing the letter "a".
How would I remove the key from the keyboard buffer/prevent it from displaying? (Side note - not sure if something like 'PeekMessage' would work - if so - does anyone know where I can find a good vb6 code sample where I can peek for stuff like 'ctrl+a' or 'ctrl+alt+a', etc, etc and then just clear the buffer, and perform my action?)
Thanks!

Answer 1

You can use a combination of RegisterHotKey and PeekMessage. The following code defines Key-A and Ctrl-A to perform actions:
Main Form
Option Explicit
Private Done As Boolean
Private Sub Form_Activate()
Done = False
RegisterHotKey Me.hWnd, &HBBBB&, MOD_NONE, vbKeyA
RegisterHotKey Me.hWnd, &HBBBA&, MOD_CONTROL, vbKeyA
ProcessMessages
End Sub
Private Sub ProcessMessages()
Dim Message As Msg
Do While Not Done
WaitMessage
If PeekMessage(Message, Me.hWnd, WM_HOTKEY, WM_HOTKEY, PM_REMOVE) Then
If Message.wParam = &HBBBB& Then
MsgBox "This is my Key-A action"
ElseIf Message.wParam = &HBBBA& Then
MsgBox "This is my Ctrl-A action"
End If
End If
DoEvents
Loop
End Sub
Private Sub Form_Unload(Cancel As Integer)
Done = True
Call UnregisterHotKey(Me.hWnd, &HBBBB&)
Call UnregisterHotKey(Me.hWnd, &HBBBA&)
End Sub
The above code works well, but in a production app I might lean towards subclassing the main window. If you prefer subclassing, you will need to use a technique of your choosing and replace the ProcessMessages method with something like this:
Private Function ISubclass_WindowProc(ByVal hwnd As Long, ByVal iMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Select Case iMsg
Case WM_HOTKEY
If wParam = &HBBBB& Then
MsgBox "This is my Key-A action"
ElseIf wParam = &HBBBA& Then
MsgBox "This is my Ctrl-A action"
End If
End Select
End Function
As you can see, subclassing is a little cleaner. Of course, you need to define the Win API stuff. So in a module, place the following code:
Module
Option Explicit
Public Declare Function RegisterHotKey Lib "user32" (ByVal hWnd As Long, ByVal id As Long, ByVal fsModifiers As Long, ByVal vk As Long) As Long
Public Declare Function UnregisterHotKey Lib "user32" (ByVal hWnd As Long, ByVal id As Long) As Long
Public Declare Function PeekMessage Lib "user32" Alias "PeekMessageA" (lpMsg As Msg, ByVal hWnd As Long, ByVal wMsgFilterMin As Long, ByVal wMsgFilterMax As Long, ByVal wRemoveMsg As Long) As Long
Public Declare Function WaitMessage Lib "user32" () As Long
Public Const MOD_NONE = &H0
Public Const MOD_ALT = &H1
Public Const MOD_CONTROL = &H2
Public Const MOD_SHIFT = &H4
Public Const MOD_WIN = &H8
Public Const PM_REMOVE = &H1
Public Const WM_HOTKEY = &H312
Public Type POINTAPI
x As Long
y As Long
End Type
Public Type Msg
hWnd As Long
Message As Long
wParam As Long
lParam As Long
time As Long
pt As POINTAPI
End Type