Three state bool

[H. Martins]

I thought I've seen some sort of tree state bool field type,
electronics speaking hi, low, hiZ..

Just my imagination? If it exists, can it be bound to a checkbox (yes,
no, grey?).

Thanks
Henry

 

[Tom van Stiphout]

On Tue, 10 Nov 2009 04:48:44 -0800 (PST), "H. Martins"

You can use a Number-type field for this, with Size=Byte.
Then by convention you can use 0 to mean hi, 1 = low, etc.

Bit fields technically can be 0, 1, null, but this will quickly give
you grief.

A checkbox is problematic but a textbox or dropdown would do nicely.

-Tom.
Microsoft Access MVP

 

[Marshall Barton]

I thought I've seen some sort of tree state bool field type,
electronics speaking hi, low, hiZ..

Just my imagination? If it exists, can it be bound to a checkbox (yes,
no, grey?).

A Checkbox control on a form can have three states when it
is bound to an Integer type number field. The three visual
states are checked, not checked and not checked gray. The
value of the field can be non-zero for cheked, 0 for not
checked or Null for gray.

Maybe you may want to use an Option Group bound to an
Integer number type field. The Option Group can contain
three check boxes with option values of your choice.