Win32/AccessMouseWheel

Option Compare Database
Option Explicit

Private WithEvents clsMouseWheel As MouseWheel.CMouseWheel

Private Sub Form_Load()
    Set clsMouseWheel = New MouseWheel.CMouseWheel
    Set clsMouseWheel.Form = Me
    clsMouseWheel.SubClassHookForm
End Sub

Private Sub Form_Close()
   clsMouseWheel.SubClassUnHookForm
   Set clsMouseWheel.Form = Nothing
   Set clsMouseWheel = Nothing
End Sub

Private Sub clsMouseWheel_MouseWheel(Cancel As Integer)
    MsgBox "You cannot use the mouse wheel to scroll records."
    Cancel = True
End Sub

Option Compare Text
Option Explicit

Private frm As Object
Private intCancel As Integer
Public Event MouseWheel(Cancel As Integer)

Public Property Set Form(frmIn As Object)
    Set frm = frmIn
End Property

Public Property Get MouseWheelCancel() As Integer
    MouseWheelCancel = intCancel
End Property

Public Sub SubClassHookForm()
    lpPrevWndProc = SetWindowLong(frm.hwnd, GWL_WNDPROC, AddressOf WindowProc)
    Set CMouse = Me
End Sub

Public Sub SubClassUnHookForm()
    Call SetWindowLong(frm.hwnd, GWL_WNDPROC, lpPrevWndProc)
End Sub

Public Sub FireMouseWheel()
    RaiseEvent MouseWheel(intCancel)
End Sub

Option Compare Text
Option Explicit

Public CMouse As CMouseWheel
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
    (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
    (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, _
     ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
     
Public Const GWL_WNDPROC = -4
Public Const WM_MouseWheel = &H20A
Public lpPrevWndProc As Long

Public Function WindowProc(ByVal hwnd As Long, ByVal uMsg As Long, _
    ByVal wParam As Long, ByVal lParam As Long) As Long
    
    Select Case uMsg
        Case WM_MouseWheel
            CMouse.FireMouseWheel
            If CMouse.MouseWheelCancel = False Then
                WindowProc = CallWindowProc(lpPrevWndProc, hwnd, uMsg, wParam, lParam)
            End If
        
        Case Else
           WindowProc = CallWindowProc(lpPrevWndProc, hwnd, uMsg, wParam, lParam)
    End Select
End Function

Option Compare Database
Option Explicit

Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
    (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
    (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, _
     ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Public Const GWL_WNDPROC = -4
Public Const WM_MouseWheel = &H20A
Public lpPrevWndProc As Long
Public CMouse As CMouseWheel

Public Function WindowProc(ByVal hwnd As Long, ByVal uMsg As Long, _
    ByVal wParam As Long, ByVal lParam As Long) As Long

    'Look at the message passed to the window. If it is
    'a mouse wheel message, call the FireMouseWheel procedure
    'in the CMouseWheel class, which in turn raises the MouseWheel
    'event. If the Cancel argument in the form event procedure is
    'set to False, then we process the message normally, otherwise
    'we ignore it.  If the message is something other than the mouse
    'wheel, then process it normally
    
    Select Case uMsg
        Case WM_MouseWheel
            CMouse.FireMouseWheel
            If CMouse.MouseWheelCancel = False Then
                WindowProc = CallWindowProc(lpPrevWndProc, hwnd, uMsg, wParam, lParam)
            End If
        Case Else
            WindowProc = CallWindowProc(lpPrevWndProc, hwnd, uMsg, wParam, lParam)
    End Select
End Function

Option Compare Database
Option Explicit

Private frm As Access.Form
Private intCancel As Integer
Public Event MouseWheel(Cancel As Integer)

Public Property Set Form(frmIn As Access.Form)
    'Define Property procedure for the class which
    'allows us to set the Form object we are
    'using with it. This property is set from the
    'form class module.
    Set frm = frmIn
End Property

Public Property Get MouseWheelCancel() As Integer
    'Define Property procedure for the class which
    'allows us to retrieve whether or not the Form
    'event procedure canceled the MouseWheel event.
    'This property is retrieved by the WindowProc
    'function in the standard basSubClassWindow
    'module.
    MouseWheelCancel = intCancel
End Property

Public Sub SubClassHookForm()
    'Called from the form's OnOpen or OnLoad
    'event. This procedure is what "hooks" or
    'subclasses the form window. If you hook the
    'the form window, you must unhook it when completed
    'or Access will crash.
    lpPrevWndProc = SetWindowLong(frm.hwnd, GWL_WNDPROC, AddressOf WindowProc)
    Set CMouse = Me
End Sub

Public Sub SubClassUnHookForm()
    'Called from the form's OnClose event.
    'This procedure must be called to unhook the
    'form window if the SubClassHookForm procedure
    'has previously been called. Otherwise, Access will
    'crash.
    Call SetWindowLong(frm.hwnd, GWL_WNDPROC, lpPrevWndProc)
End Sub

Public Sub FireMouseWheel()
    'Called from the WindowProc function in the
    'basSubClassWindow module. Used to raise the
    'MouseWheel event when the WindowProc function
    'intercepts a mouse wheel message.
    RaiseEvent MouseWheel(intCancel)
End Sub

Option Compare Database
Option Explicit

'Declare a module level variable as the custom class
'and give us access to the class's events
Private WithEvents clsMouseWheel As CMouseWheel

Private Sub Form_Load()
    'Create a new instance of the class,
    'and set the class's Form property to
    'the current form
    Set clsMouseWheel = New CMouseWheel
    Set clsMouseWheel.Form = Me

    'Subclass the current form by calling
    'the SubClassHookForm method in the class
    clsMouseWheel.SubClassHookForm
End Sub

Private Sub Form_Close()
    'Unhook the form by calling the
    'SubClassUnhook form method in the
    'class, and then destroy the object
    'variable
    clsMouseWheel.SubClassUnHookForm
    Set clsMouseWheel.Form = Nothing
    Set clsMouseWheel = Nothing
End Sub

Private Sub clsMouseWheel_MouseWheel(Cancel As Integer)
     'This is the event procedure where you can
     'decide what to do when the user rolls the mouse.
     'If setting Cancel = True, we disable the mouse wheel
     'in this form.
     MsgBox "You cannot use the mouse wheel to scroll through records."
     Cancel = True
End Sub