[Lazarus] Carbon: Simple component in a simple package with strange behavior

[Tom Gregorovic]

On Fri, May 30, 2008 at 12:20 PM, Bent Normann Olsen <bent at earmaster.com> wrote:
> Hi all,
>
> Lately I've been trying to create a package with custom components, which
> works already on Lazarus Win32, but gets all kinds of errors on Mac OS X, so
> I created a package from scratch and try to isolate different problems.
>
> I created a new package and saved it as "TestPackage.lpk", added a new
> component with TWinControl as ancestor type and named it TCommonTest, named
> the unit NewCtrls and saved the unit as newctrls.pas. I added a new
> requirement to the package, so that LCL also is required by the new package.
>
> I then manually added a new component to the unit named TComponentTest with
> TCommonTest as ancestor, and changed the register procedure to only register
> the last component.
>
> It compiles, and the component is installed, and the component is visible in
> the tab "New Ctrls" on Lazarus, which is compiled to Carbon.
>
> But when I try to drop the new component on a form (on a new and clean
> application) it fails saying "Error moving component
> ComponentTest1:TComponentTest". The new component does not appear on the
> Object Inspector at first, but clicking on the component tree will make it
> appear, and I also can select the component on the form - but nothing is
> added to the unit source, and the application can't run because of Class
> "TComponentTest" not found, which naturally is caused by nothing was added
> to the units uses clause.
>
> Manually making the changes to the forms unit will cause the application to
> raise an exception with the message: "(V)TCarbonWSWinControl.CreateHandle
> Error:Not implemented - unable to create Carbon win control for
> ComponentTest1:TComponentTest!"
>
> Does a new component with an ancestor type of TWinControl need special
> handling, or is it impossible? Or am I doing something totally wrong?
>

Hi,
each TWinControl descendant needs to have implemented creation of
underlying Carbon control. If you want to use generic TWinControl, you
have to choose TCustomControl.

Tom