[Zope] ZClass "add" question

[James W. Howe]

I've defined a new ZClass complete with customized form and add 
methods.  The form displays some fields for the user to enter values into 
and the add method creates the ZClass and updates properties and adds 
content to the ZClass based on information entered by the user from the 
form.  Depending on what is entered by the user, my add method may create 
new objects to store in the ZClass.  My problem is that I can't seem to 
find a way to determine whether a user entered information.  For example, 
my form defines fields where the user can specify the name of an image file 
along with some information about an image.  If the user does not specify 
an image file, I don't want to add a new ZClass instance which would hold 
information about the image.  In my add method, I've tried doing something 
like this:

<dtml-if "REQUEST['photoFile']">
      <... add the image ...>
</dtml-if>

That didn't work.  Regardless of whether I entered information in photoFile 
the code inside the dtml-if got executed.

I then tried:

<dtml-if "REQUEST['photoFile'] and REQUEST['photoFile'] != ''' ">
    <... add the image ...>
</dtml-if>

This also failed.  I added a <dtml-raise> tag to dump the contents of 
'REQUEST['photoFile'] and it came out as ''.  I don't understand why the 
code inside the dtml-if is executing.  I'm sure that I'm doing something 
incredibly stupid, but I can't figure out what.    Can anybody offer me any 
guidance?

Thanks.


James W. Howe				mailto:jwh@allencreek.com
Allen Creek Software, Inc.		pgpkey: http://ic.net/~jwh/pgpkey.html		
Ann Arbor, MI  48103