[mol]

I usually use the following procedure to trap mouse wheel messages when the cursor is over a control:

procedure TForm1.MouseWheelHandler(var Message: TMessage);

var

Target: TWinControl;

begin

Target := FindVCLWindow(SmallPointToPoint(TWMMouseWheel(Message).Pos));

if Assigned(Target) then

Target.Perform(CM_MOUSEWHEEL, Message.WParam, Message.LParam)

else

inherited MouseWheelHandler(Message);

Message.Result := 1;

end;

This works for all controls – no matter if they are located on a frame or form. The scrollbars of the control react to movements of the mouse wheel. The only exception is an sScrollbox which is sitting on a frame within an sFrameBar. I cannot get the sScrollbox to react to the mouse wheel when the cursor is over the control.

So, how do I do that?

Steps to reproduce:

Put an sFrameBar on a form

Create a TFrame and drop an sScrollbox on it

Place a few panels on the sScrollbox

Run the program and reduce size so that the vertical scrollbar of the scrollbox becomes visible

Place mouse cursor over scrollbox and move the mouse wheel

Nothing happens

Thanks!

[Support]

Hello

Maybe this is standard behavior?

Can you check the TSrollBox component please?

Here I uploaded the test-app by your problem description. It's correct?

[mol]

Yes, your test application shows the behaviour I was experiencing. In the meantime, I have found an old solution posted by Peter Below for a related problem:

Quote:

“The main problem seems to be that the scrollbox does not take focus when clicked on, and the MS Intellimouse driver will only send WM_MOUSEWHEEL messages to the control with focus. So the messages go to the form.”

procedure TForm1.FormMouseWheel(Sender: TObject; Shift: TShiftState;

WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);

begin

if PtInRect(scrollbox1.BoundsRect, ScreenToClient(Mouse.CursorPos)) then

scrollbox1MouseWheel(Sender, Shift, WheelDelta, MousePos, Handled);

end;

procedure TForm1.scrollbox1MouseWheel(Sender: TObject;

Shift: TShiftState; WheelDelta: Integer; MousePos: TPoint;

var Handled: Boolean);

var

msg: Cardinal;

code: Cardinal;

i, n: Integer;

begin

Handled := true;

if ssShift in Shift then

msg := WM_HSCROLL

else

msg := WM_VSCROLL;

if WheelDelta > 0 then

code := SB_LINEUP

else

code := SB_LINEDOWN;

n:= Mouse.WheelScrollLines;

for i:= 1 to n do

scrollbox1.Perform(msg, code, 0);

scrollbox1.Perform(msg, SB_ENDSCROLL, 0);

end;

The above works with a regular scrollbox, but I haven't checked with the sScrollBox. Anyway, I hope this helps others in the future.

[Author]

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