On Sat, 06 May 2006 13:26:44 +0200
Giuliano Colla <[EMAIL PROTECTED]> wrote:
> Re-checking the patch I sent yesterday for Qt interface TMemo, I saw
> that I'm not sending an OnChange Event when the TMemo is
> programmatically changed. That is OnChange is generated only on user
> input on the memo.
>
> The correction is trivial, just a few lines of code, but the
> philosophical question arises. Maybe it's already been discussed and
> settled since a long time, but I'm a newcomer.
>
> The OnChange event exists only in controls which may be subject to user
> input, such as TEdit, TMemo, TComboBox TTrackBar and such.
>
> For some of them it's reasonable to think that the same action which
> must be taken when the user changes something should also be taken when
> the program changes it (such as TTrackBar): this saves code.
>
> For others, as TMemo, TEdit, and perhaps TComboBox, generating the
> OnChange event when the change comes from the program is IMHO more a
> nuisance than a feature. In my experience I've always been forced to add
> code in order to tell apart user input from changes coming from the
> program. Otherwise unwanted effects and/or unwanted circles are generated.
Me2.
> So the philosophical question: is it right to follow Delphi logic for
> TEdit and TMemo OnChange, or it would be more reasonable to "improve"
> the matter, and generate OnChange only on user action?
IMHO we need both.
For Delphi compatibility we should follow the VCL behaviour here.
Maybe a Delphian can test and tell us.
Mattias
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