Ok, so hopefully I can explain this complex issue properly.
I have a menu view which includes a weather view that works on GPS coordinates. I tried just using the session gps coordinates and it works on mobile devices but not on PC's (possibly my IT is blocking this?)
SO, I have another view, a map view with lots of layer UI items that are various hardware devices shown on the map and you can click on those and bring up the status popup for those devices and within that info there are individual coordinates for each marker.
I want to be able to move the coordinates for any selected marker on the map into a custom session lat / lon parameter and then have my weather view read from that session custom lat / lon parameter and show the weather for which item the use opens.
I'm trying to do that now with some translation but it doesnt seem to actually populate in the custom session prop lat / lon.
Check out system.util.sendMessage(). You can send parameters in a message and whatever component receives it can then use that information.
the example here is using a tag, is it somehow possible to do using a parameter instead?
Just to make sure I understand, are you using a tag to store the session lat/lon values? If that is the case then you could use system.tag.readBlocking() to retrieve that value; however, because tags are global the value would be shared, so if you had multiple sessions running they would all share the values.
To make it more dynamic I would recommend using a custom property on whatever view/component you want to send the values to.
Im trying to use a custom property, not a tag, but the link you posted shows an example of how to use a tag.
I might not be understanding what is happening but I have a hunch that the Lat isn't changing so the binding doesn't fire.
You're showing a binding on Lat_Holder which will update if "this.custom.Lat" changes.
What's the binding for "this.custom.Lat" look like?
Replace your property binding with this expression binding:
toFloat({this.custom.lat}, {session.custom.lat})
Though I'm not sure session customs are the place to store these.