Check for file type

I was attempting to use dynamic rules to limit file types to be uploaded. I would check the extension of the file (using an if statement, the right function, and totext[File]).

However, I noticed if you delete a file, it must cache or something because ToText([File]) will still show the file name, even after deletion!

Anyone have insight on this, or how to limit a file upload to a certain type? To test yourself:

Create a file field
Create a formula text field: ToText([File Field])
Upload a file and note the formula field.
Delete the file and note the formula field. It will remain with the old file name.

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Mike Tamoush
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