Using Mouse Wheel into the Memo Box or Combo Box in Access Forms

Question

I have an Access form named "NewStaff" that contains a Memo box. When I clicked inside it, rolling the mouse wheel would cause an exit to this field and it would not be placed on the text inside the Memo box. Finally, I put the following code on the MouseWheel Event form and now I can move the Memo box lines by rolling the mouse wheel.

 Private Sub Form_MouseWheel(ByVal Page As Boolean, ByVal Count As Long)
         Dim i As Long
         Dim s As String
         If Me.ActiveControl.Name = "ُNewStaff" Then
             If Count > 0 Then
                 For i = 1 To Count
                     s = s & "{DOWN}"
                 Next i
             Else
                 For i = 1 To -Count
                     s = s & "{UP}"
                 Next i
             End If
             SendKeys s
         End If
 End Sub

The problem is that the cursor has jumping three lines to three lines and finally leaves the field!

Is there a way to go line by line and stay in Memo box for the cursor? ... Thanks

Answer 1

Using SendKeys UP/DOWN to scroll is clunky - users don't necessarily want the cursor to move, only the text to scroll. Plus the "sudden exit" effect you noticed.

A long time ago I found and adapted this solution.
Paste all the code into a module, and call it as shown in the comments.

Option Compare Database
Option Explicit

Private Const WM_VSCROLL = &H115
Private Const SB_LINEUP = 0
Private Const SB_LINEDOWN = 1

Public Declare Function SendMessage Lib "user32" _
   Alias "SendMessageA" _
   (ByVal hWnd As Long, _
   ByVal wMsg As Long, _
   ByVal wParam As Long, _
   LParam As Any) _
   As Long
   
Private Declare Function apiGetFocus Lib "user32" _
        Alias "GetFocus" _
         () As Long
'

' Scroll multi-line textboxes with the mouse wheel. The textbox must have the focus.
'
' Call this sub in the MouseWheel event of the form(s) containing multi-line textboxes, like this:
'
' Private Sub Form_MouseWheel(ByVal Page As Boolean, ByVal Count As Long)
'    Call MouseWheelScroll(Count)
' End Sub
'
' Sources
' http://www.access-programmers.co.uk/forums/showthread.php?t=195679
' http://www.extramiledata.com/scroll-microsoft-access-text-box-using-mouse-wheel/

Public Sub MouseWheelScroll(ByVal Count As Long)

    Dim LinesToScroll As Integer
    Dim hwndActiveControl As Long
    
    If Screen.ActiveControl.Properties.Item("ControlType") = acTextBox Then
        hwndActiveControl = fhWnd(Screen.ActiveControl)
        For LinesToScroll = 1 To Abs(Count)
            SendMessage hwndActiveControl, WM_VSCROLL, IIf(Count < 0, SB_LINEUP, SB_LINEDOWN), 0&
        Next
    End If

End Sub

' Source: http://access.mvps.org/access/api/api0027.htm
' Code Courtesy of Dev Ashish

Private Function fhWnd(ctl As Control) As Long
    
    On Error Resume Next
    ' We only use this function for Screen.ActiveControl, so this is not necessary.
    ' I can't remember if I found it harmful in some situations.
    ' ctl.SetFocus
    
    fhWnd = apiGetFocus
    On Error GoTo 0
    
End Function