[DUG] Validate data entry

[Colin Johnsun]

Hi Wallace,

Don't know if you missed my post or not but if you do your validation on the
OnDataChange event on the TDataSource component, it gets triggered everytime
you modifiy a field value. So if you are in a DBGrid and you change a value
in a column and then move to the next column, the event is fired.

OnValidate happens before posting but OnDataChange occurs whenever a field
is modified of if you scroll to new record.
If you move to a new record you just ignore it by testing the Field
parameter is nil.

Cheers,
Colin

On 2 June 2011 18:00, Marshland Engineering <marshland at marshland.co.nz>wrote:

>  >Form inheritance or Frames to cut
> >down on the number of different entry points.
>
> The program is set of sequences for machining. A DBGrid displays the
> operations.
>
> On double clicking the DBGrid operation, opens a form with the relevant
> data and the graphics is displayed.
> The data entry points are placed on the graphic at the point of interest.
> So each entry form is completely different.
>
> The machining steps are
>
> Thread, Rough Turn, Plunge cut, Face etc and all can be internal as well.
>
> However for example - each form has a Depth Of Cut that has a range of 0.02
> -2.5 mm.
>
> My thoughts
>
> -Create a new DB aware component that has a maximum and minimum range and
> use it on each form. Not ideal as I have to ensure consistency between all
> forms.
>
> -If I use OnValidate in the DM, when is this event triggered? On Post ?
> If so then I could have several errors occurring at the same time when the
> data validated, which error belongs to which field ?
>
> If I use OnValidate - when I append a record, will it run all the
> OnValidate procedures at once ?
>
> It looks like I may have to split the operation into to parts - check that
> the data entered is in the correct format (Form Property) and another to
> check it is in the right range (Database Property)
>
> PS Why Delphi didn't have a DBEditNumeric or EditNumeric  component I'll
> never know.
>
>
> Thanks Chaps.
>
>
>
>
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