So, you’re customizing a SharePoint list form, and you want to make the File Attachments be read-only at some point.  Well, the popular consensus around the interwebs is that this just can’t be done.  Create an InfoPath form from scratch and publish to a library yada yada yada.  Well I beg to differ.  InfoPathians 4:13 says “All Things Are Possible Through Rules And Formulas Who Strengthen Me”.

In your data source, Attachments is a group, with attachmentURL as a repeating field within.  So what you want to do is:

1. In your Fields pane, click on “Show advanced view”
2. Expand “Attachments” group so you can see attachmentURL field
3. Click on attachmentURL and drag it into your form wherever you want the links to be
4. When presented with options, choose Repeating Section with Controls
5. Click inside the Repeating Section and press CTRL + K to add a Hyperlink
6. Under Link To, for Data Source, just type a period (this uses the current value of the repeating field, which is the URL to the attachment file
7. Under Display, you can either type a period again to use the full path as the display text,

Now if you want to get fancy and only show the filename, instead of the entire URL path, you will have to use a formula to remove the beginning of the URL The URL generally looks like “https://mydomain.com/sitename/List/listName/Attachments/###/filename.ext “, where ### is actually the ID of the list item and will be different with every item.  So we need a function that gets the substring AFTER the last /.  Since there is no way to get the last occurrence of a string, and the ID changes with each list item, we can hardcode the part up to the ID number, and then get substring after the /, with a formula like this:

substring-after(substring-after(., “https://mydomain.com/sitename/Lists/listName/Attachments/”), “/”)

And voila!  Read only access to file attachments!  You’re welcome  Oh.. what’s that?  The link is broken?  Not possible.  Really?  Damn.  Ya, I got that too.  Comparing the URL of the file attachment to the URL in the regular control, the only difference I could see was that the spaces in the URL were encoded in the regular control.  But doesn’t the browser automatically take care of that?  Yes it does!  Except when it doesn’t.  And in this case… it doesn’t.  Crap. Ok, let’s use a formula to fix that then.  Translate SHOULD do the trick.  How about

translate(., ” “, “%20″)

Ok great we’re done!  Except that it doesn’t work.  But when I put use it as a the formula for a Calculated Value it displays the URL perfectly!  Crap again.  Well, I was able to get it working for a URL that had only a single space in it by simply concat-ing the string before the space, to “%20″, to the string after the space like this:

concat(substring-before(., ” “), “%20″, substring-after(.,” “))

I will update this post if I come up with a solution for multiple spaces (or feel free to post them in the comments if you have one!)