Skill: creating FormFields with ?modifyCallback

Dear All,

I have created a Form with an InputField using hiCreateStringField()
and I want to check the entered string if it has reached a length of 10
(during typing).
Therefore I use the ?modifyCallback argument as follows:

***
l_field=list(hiCreateStringField(
?name 'strfield
?prompt "Prompt"
?modifyCallback "if(strlen(Form->strfield->value)<=10
then x=t
else x=nil)"
?value "xyz"
) 0:30 200:30 100)
***

The Form works properly until I try to enter something into the field.
Then I get this:

Form->strfield->value="xyzq"
*Error* eval: not a function - 'strfield
*Error* car: Can't take car of atom - ERROR

What have I done wrong?

Regards

Flash

 

The value of the field itself doesn't contain the value you want to verify,
so what you are doing wouldn't work even if it weren't the wrong thing to do
in the first place. The modify CB is passed arguments: the field name, the
new value, and the source of the change (t for programmatic, nil for user
entry).

The return value from the modify callback will be t for "accept the change",
nil for "reject the change", and a different value for "replace changed value
with this value".

You want to do something like:

(defun MyModifyCB ( field value changeSource ) strlen(value)<=10)

l_field=list(hiCreateStringField(
?name 'strfield
?prompt "Prompt"
?modifyCallback "MyModifyCB"
?value "xyz"
) 0:30 200:30 100)

-Pete Zakel
()

"The man who sets out to carry a cat by its tail learns something that will
always be useful and which will never grow dim or doubtful."
-Mark Twain