Deleting image on checkbox

Hi - I have an update form that is using DFP to upload an image.

I want to include a checkbox to delete the file and it's associated entry in field for the article record.

I have the file part figured out - it deletes the file properly if deleteimage is checked:

<?php
$WA_DeleteFileResult1 = false;
if(("". ((isset($_POST["deleteimage"]))?$_POST["deleteimage"]:""). ""
!= "")){
$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("cmsassets/featureimages/", "".$row_WADAarticles['article_imagefile'] ."");
}
?>

But I can't figure out how to make the article_imagefile field blank if deleteimage is checked. I'm trying to change the default image, figuring if that was blank on update it would solve this. I've tried:

My checkbox in the form:
<input name="deleteimage" id="deleteimage" type="checkbox" value="1" />

and also in the form:
<input type="hidden" name="article_defaultfile" id="defaultfile" value="<?php if(("". ((isset($_POST["deleteimage"]))?$_POST["deleteimage"]:""). ""
!= "")){ ?><?php } else { ?><?php echo($row_WADAarticles['article_imagefile']); ?><?php } ?>" />

But no workie.

Any help would be appreciated! Is this the right way to do this?

Do you have DataAssist?

The way that I do this is to use the Update Behaviour. Now, to the best of my knowledge you cannot enter a blank value using this, so what I do is place some text in the field I want to update (the file field), say ABC and then save the behaviour so the code is written to the page.

Then go into the code view and simply remove the ABC text from the code so that the string is empty.

You could also have an empty hidden field on the form and bind that to the file field on update, as long as the trigger of the update is your checkbox.

Hope that helps?

Cheers
Ian