Access violation while changing the theme

[tim-lebedkov]

Access violation while changing the theme

[tim-lebedkov]

In the following method FVertScrollWnd is nil, but Self is not nil:

destructor TVclStyleScrollBarsHook.Destroy;
begin
  FVertScrollWnd.StyleHook := nil;
  FreeAndNil(FVertScrollWnd);
  FHorzScrollWnd.StyleHook := nil;
  FreeAndNil(FHorzScrollWnd);
  inherited;
end;

[joachimmarder]

Well, I no more have a Delphi XE5 at hand, but I remember that at least in XE2 - XE5 the VCL style code was not the best. Besides updating to a newer Delphi version, you can try if simply adding assign checks solves the problem:

destructor TVclStyleScrollBarsHook.Destroy;
begin
  if Assigned(FVertScrollWnd) then
  begin
    FVertScrollWnd.StyleHook := nil;
    FreeAndNil(FVertScrollWnd);
  end;
  if Assigned(FHorzScrollWnd) then
  begin
    FHorzScrollWnd.StyleHook := nil;
    FreeAndNil(FHorzScrollWnd);
  end;
  inherited;
end;

If so, I will add this change.

[tim-lebedkov]

The change helps. Thank you.