Re: [Oorexx-users] ooDialog - getCaretPos

[Mark M. <mie...@gm...>]

On Thu, Jun 16, 2011 at 3:31 PM,  <os...@si...> wrote:

> Working through the detail of your numeric check of data in an edit control,
> I noticed that the "getCaretPos" method is not in build 6965 of the ooDialog
> ref. I checked in several of the source files, but couldn't find it. Can you
> tell me please which ooDialog source file I should look in?
>
> The statement in your EditDecs file (in the 'onUpdate' method) was:
>  pos = self~getCaretPos(ecDecNum2) - 1

The getCaretPos() method is a method I wrote in the example program,
it is a method I added to my dialog subclass.

::method getCaretPos private

> Btw, I wondered why this is not a method on the edit control itself rather
> than on the dialog.

It is not a method of the .Edit class because the Windows API used
with Edit controls does not have such a method.  That doesn't mean the
method couldn't be added to the .Edit class, it just means no has
thought to do so, as of yet.

In the Windows API, the EM_GETSEL edit control message is defined as:
"Gets the starting and ending character positions of the current
selection"  and in the Remarks section of the Windows documentation
for that message it says:

If there is no selection, the starting and ending values are both the
position of the caret.

So, that is a relatively simple way to get the character position of
the caret, and is what I used.  However, it is not foolproof.  If you
do have a selection, the caret will be either at the end of the
selection, or the front of the selection - depends on if you selected
from right to left or from left to right.

> This is an area that seems a little confusing. Is there
> a principle I can apply to predict whether a method is on a control object
> or on a dialog object?

In general there is no principle here.  This was confusing I think
because you didn't notice that I had defined the method in my program.
 In general, at this point in ooDialog, I don't think there are any
methods for controls that are defined on the dialog object, that don't
have a matching method in the control itself.

My personal belief is that during the history of ooDialog too many
methods were added to the dialog object, that did not belong to a
dialog object.  Among these are methods like getListWidth and
setListWidth that set or get a list box width.

I never use methods of the dialog object that should be dialog control
methods.  If I need to do something with a dialog control, I use a
dialog control object.

--
Mark Miesfeld