Mouse wheel scrolling on VB6 compiled app (not the IDE)

I would like to add mouse wheel scrolling to an old VB6 app. I am not bothered about adding it the IDE, just the compiled app. I have tried a few of the hundreds of examples on "the internet" but haven't yet found a reliable one that works on all forms. I did try one that worked only on Flexgrids and it wasn't bad but I had one or two unexplained crashes. The software I would like to add the scrolling to runs on Windows 10 and Windows 11 PCs - all 64-bit.

So, has anyone found a reliable, consistent method of adding mouse wheel scrolling to VB6 apps?

did u try subclassing?
thats what most people are using.

very easy.
create a project, add this in Form_Load

StartClassing Me.hWnd

add a module:

Code:

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Private Const WM_NCDESTROY = &H82
Private Const WM_MOUSEWHEEL = &H20A

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

Dim OldWindowProc&

Sub StartClassing(ByVal hWnd&)
    OldWindowProc = SetWindowLong(hWnd, -4, AddressOf SubClassingProc)
End Sub

Function SubClassingProc(ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    Select Case Msg
        Case WM_NCDESTROY: SetWindowLong hWnd, -4, OldWindowProc
        Case WM_MOUSEWHEEL: Form1.Caption = CStr(wParam)
        Case Else
            SubClassingProc = CallWindowProc(OldWindowProc, hWnd, Msg, wParam, lParam)
    End Select
End Function

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Yeah, I use subclassing too. Because this is an unraised event in VB6 about the only two ways I could think of to do this would be:

1) Subclassing, to raise the mouse wheel events.
2) Possibly a very fast timer to see if the mouse wheel as changed.

I've never done #2, but I certainly wouldn't recommend it, as fast timers are just going to chew up your computer's resources. Subclassing is really the only way.

Thanks for your help. I assume this is just partial code to demonstrate the principle? The form caption alternates between 7864320 on scroll up and -7864320 on scroll down. I guess I could use that as a flag to increment or decrement the scroll position of my (in this case) MSHFlexgrid.

yeah exactly. this is just the basics. u need to implement what u want to react with the wheel.

remember that subclassing can crash your application.
so ALWAYS save your project before u run it.

Quote:

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Originally Posted by baka

yeah exactly. this is just the basics. u need to implement what u want to react with the wheel.

remember that subclassing can crash your application.
so ALWAYS save your project before u run it.

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Many thanks. I'll see what I can come up with. My users have been running the software for 15 years without mouse wheel scrolling but it bugs me that it doesn't work!

The two windows messages I monitor for in the subclassing procedure are:

Code:

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    Const WM_MOUSEWHEEL    As Long = &H20A&
    Const WM_MOUSEHWHEEL    As Long = &H20E&

---

And then I just look for wParam being greater or less than zero to determine up or down (or left or right for WM_MOUSEHWHEEL).

Quote:

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Originally Posted by paulg4ije

My users have been running the software for 15 years without mouse wheel scrolling but it bugs me that it doesn't work!

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VB6 came out before mouse wheels were popular.

If it’s about scrolling the MSFlexGrid then check this thread
https://www.vbforums.com/showthread....th-Mouse-Wheel

Thanks everyone.