Keep the following guidelines in mind when using
references in your application:
Currently, you can create references to
windows, window fields, table buffers, table fields and menus.
When a reference is assigned, the resource
the reference points to must be available. For example, you can’t
create a reference to a window field if the form containing the
window isn’t open.
When using a reference to a table, you
must refer to the keys for the table by number. You can’t use the
names of the keys, because the table isn’t known at compile
time.
If a resource is no longer available, any
reference to that resource is no longer valid. For example, if a
table is closed, any reference to that specific table buffer
instance is no longer valid. Reopening the resource does not
make the reference valid.
A reference is not notified when it is no
longer valid.
When creating a reference to an array
field, you must reference a single element in the array. You can’t
make a reference to the entire array.
You can use reference fields as components
of a composite fields.