The "Param" function DOES NOT WORK on SharePoint custom forms inside of SharePoint itself (which is where they are designed to run!!!!).
I created a form, with a custom Data Card with two label controls - one with a Text property set to "ParamValue:", and the other with the "Text" property set to:
Param("Param")
Published the form, browsed to my list, and then put a "Param" query string parameter in the URL, like this:
https://<tennant>.sharepoint.com/<site>/Lists/<MyList>/AllItems.aspx?Param=Hello
The customized form simply does not retrieve the param value:
Looking at the browser source when I browse to the SharePoint list, I can see that the form is embedded in an iframe. So I mashed up a URL based in the information I found in browser source, and browsed to the customized form using a similar URL:
https://web.powerapps.com/webplayer/app?appId=/providers/Microsoft.PowerApps/apps/<AppIdGoesHer>&Param=Hello
The parameter value was picked up fine:
This means that if we want to pass information to a PowerApps form from another part of SharePoint (e.g. from a page added to SharePoint or a custom Document Set page), we either have to:
Having the "Param" function not work in a SharePoint custom form seems to be a big gaping hole. Can this be fixed please?