Lucky for you I just figured this out today myself ;)

Here goes:

You need to be sure that the param/value you are trying to change is
actually present, otherwise the fieldsvisible[0] is going to put you
out of bounds for the StringList.

I prefer the following code:
FieldsVisible.Values['FieldName'] := 'FALSE';
I believe that this syntax will add the value to the StringList if it
isn't already there. If not, you will need to add it with an
add('FieldName=FALSE')

Good luck.

George



--- In IBObjects@yahoogroups.com, "Paolo Fenelli <paolopf@l...>"
<paolopf@l...> wrote:

> Hi list,
> i need to change the visible property of fields in a TIB_Query at
> runtime
> i've tried:
> with IB_Query do
> prepare;
> fieldsvisible[0] := 'FieldName=FALSE';
> open;
> end;
> but it raises the exception:
> List index out of bounds(1)
>
> Any help appreciated.
>
> Paolo Fenelli