Subclassing ... MouseScroll ... Someone Please READ | Project Samples Avail!

Hey All ... (I'm going mad here .. ) ... I've been trying to get this to work for the last 4 hours but I don't know a whole lot about subclassing so here is my situation ..


I've made a usercontrol (I pass a form name to the control and it paints the form into a PictureBox, and scrollbars in the usercontrol allow the user to scroll about) ... but I want the user to be able to scroll the form with a wheel mouse, so earlier on I searched the forums and came up with two different peices of cone, one which is very basic other highly complex with all sorts of error detection / os detection ect ... in anycase the WM_MOUSESCROLL message isn't being fired as far as I can't tell. (I am debug.printing all the messages being sent to the specified function) ... I see it being called when I move the mouse from control area control area / mouse clicking ect ...

I've tried using this in a seperate project (just a scrollbar and the form) and it works just fine. So because I used SetParent() to paint the form into a picturebox cause a problem somehow ? ...

Any Ideas / Suggestions would be appriciated.

anyone ?

http://msdn.microsoft.com/library/de...MOUSEWHEEL.asp

It works :)

VB Code:

Private Const WM_MOUSEWHEEL As Long = &H20A

sorry .. I am using WM_MOUSEWHEEL, and i have gotten it to work in a test project .. it just won't work in my app ..
(module I'm using for mouse scroll)

VB Code:

Option Explicit
Declare Function SetWindowLong& Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long)
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
Const GWL_WNDPROC = (-4)
'These are the messages
Const WM_MOUSEWHEEL = &H20A
Global WndProcOld As Long
 
Public Function WindProc(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
'checks the messages
    Debug.Print "wMsg Is : " & wMsg
    Debug.Print "Mwheel  : " & WM_MOUSEWHEEL
    If wMsg = WM_MOUSEWHEEL Then
        If wParam < 0 Then
            'If Form1.VScroll1.Value <> Form1.VScroll1.Max Then Form1.VScroll1.Value = Form1.VScroll1.Value + 1
            Form1.FormScroll.vs_Change
        Else
            
            'If Form1.VScroll1.Value <> Form1.VScroll1.Min Then Form1.VScroll1.Value = Form1.VScroll1.Value - 1
            Form1.FormScroll.vs_Change
        End If
    End If
    WindProc = CallWindowProc(WndProcOld&, hwnd&, wMsg&, wParam&, lParam&)
End Function
 
Sub SubClassWnd(hwnd As Long)
    WndProcOld& = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf WindProc)
End Sub
 
Sub UnSubclassWnd(hwnd As Long)
    SetWindowLong hwnd, GWL_WNDPROC, WndProcOld&
    WndProcOld& = 0
End Sub

Where Form is Subclassed:

VB Code:

Public Sub Form_Draw(MyForm As Form)
 
Set PForm = MyForm
Dim xx As Long
 
xx = GetWindowLong(MyForm.hwnd, GWL_STYLE)
SetWindowLong MyForm.hwnd, GWL_STYLE, (xx Or WS_CHILD)
xx = SetParent(MyForm.hwnd, Image1.hwnd)
    'Mouse scrolling
    SubClassWnd MyForm.hwnd
Image1.top = 0
Image1.left = 0
MyForm.Move 0, 0
MyForm.Show
Image1.Height = MyForm.Height
Image1.Width = MyForm.Width
 
    Debug.Print MyForm.Height
    Debug.Print UserControl.Height
    If MyForm.Height <= UserControl.Height Then
        vs.Enabled = False
    Else
        vs.Enabled = True
        vs.Min = 0
        vs.Max = (MyForm.Height - vs.Height) / 4
        vs.Value = 0
    End If
    
    If MyForm.Width <= UserControl.Width Then
        hs.Enabled = False
    Else
        hs.Enabled = True
        hs.Min = 0
        hs.Max = (Image1.Width - hs.Width) / 4
        hs.Value = 0
    End If
End Sub

and sorry Image1 is a Picturebox not an image control :P

You got the latest drivers for your mouse?

hummm .. I've said serveral times that I've gotten it working (in a new project) ... it does not work in my main app


Picture having a usercontrol with a picturebox and two scrollbars (VS and HS) ...
(Scrollform control is say on Form1 ... I call ...

VB Code:

ScrollForm.Form_Draw Form3

which calls the above procedure ...

That procedure uses SetParent() to place the form inside of the picturebox (so that Form3 more or less becomes part of Form1, not really sure how to explain it - the title of the main form won't loose focus, although I'm not sure that Form3 can actually gain focus anymore *shrug*)

Here is a screen to give you a better idea .. Form3 is the one that displays all the information...

I see what you mean. With a similar project (I think), the mouse wheel message is picked up once, and not at all until re-subclassed. Strange

In a New Project ...

1 Form
1 Vertical Scrollbar
No Custom Usercontrol
No Use Of SetParent() (as there is only one form)

Works Fine ...

Using it in my main app shown in the screenshot above, it doesn't work .. No mouse wheel events are sent .. I'm not sure if it's because the form can't get proper focus or what but it's really annoying and bothering me to no end. *Tears hair out*

Quick Sample Project (with setparent)

Quick Sample Project (without setparent)
*works

*bump