I was recently asked by a client to have a custom .NET page displayed on an entity form. Because of the content of the page (it’s a heavy, long and large!), we were all in agreement that using an IFRAME or a web resource in a Tab or Section on the main form was not going to be pretty. The best user experience is to have the page displayed when users click on a navigation link on the left menu.
Sounds easy, right? Not so fast! In our case, the custom web page displays content that is specific to the record it’s opened from. That means the page needs to know the ID of the record. That sounds easy as well, right? You are thinking simply pass the record ID as parameter in the query string… Yes, it works with an IFRAME and for a Web Resource, you can change the URL programmatically when the form loads or when a field value is changed. For a Navigation Link, not so fast! There is no supported way to change the URL programmatically!
This had me do some research to see what we could do to get around that limitation. Unfortunately, it has to be a non-supported approach.
You could attach to the On Click event of the navigation link or set the URL on load of the form. Regardless, problem is accessing the IFRAME in which your page resides. There are a few ways to do this as you can see here and here. I prefer solution 1 because you use the ID of the navigation URL (it is transported as part of the CRM solution and remains the same in all environments).
I want to say I hope Microsoft adds this functionality in a future update but with the new process driven UI forms that are coming in the Orion release, I don’t know if all this will still be relevant in a near future. We’ll see!