I am trying to tidy up my code now that Delphi XE2 is available - my code dates from Borland Pascal 7 so there are lots of 'old' (but working!) Win32 techniques and natually I have platform independence in mind too. Support for the mouse wheel has come up before here with several prior questions 1 2 and 3. As with some of these answers, my own solution is a simple mouse message intercept using a TApplicationEvents component:
procedure TForm6.ApplicationEvents1Message(var Msg: tagMSG;
var Handled: Boolean);
procedure ProcessMouseWheelMessage;
begin
Msg.message := WM_KEYDOWN;
Msg.lParam := 0;
If Integer(Msg.wParam) > 0 then
Msg.wParam := VK_UP
else
Msg.wParam := VK_DOWN;
Handled := False;
end;
begin
Case Msg.message of
WM_MOUSEWHEEL :
ProcessMouseWheelMessage;
end;
end;
I revisited this code today because 'Msg.wParam' is now NativeInt, breaking use of negative Msg.wParam values in the above code unless you use Integer(Msg.wParam). It made me notice that I had not seen any really definitive use of the mouse wheel for Delphi code - terrible when all mice now have wheels and Delphi is at the 'cutting edge' again! I would have expected a property, a component or some other more 'exposed' solution, and what about Fire Monkey wheel support?
Do I carry on with my solution or is there a better way?
