Maps - when pins are loaded on the map and user moves map, how to only load new pins and not the ones already loaded?

Question

I'm trying to load only new pins when a user moves the map, like, he sees pins, then makes a move to a side and new pins load and get displayed on the map but the ones that were displayed already don't need to load up again, they just stay there.

I know how to refresh the map etc. but I don't want to load all the pins every time the user moves the map, I want the ones already displayed to stay and the new ones to load on the map.

I thought about adding the pins to a List<Pin> and when I need to load new places I could add the new ones to the list, but then it reloads the whole list and so the current pins are reloaded as well.

If you could share the way to do it so that I can understand the thought process and then I can share code if needed because otherwise it's going to be a super long post with a bunch of code that might not be needed to understand how to do it.

Answer 1

You could use ObservableCollection instead of List in ViewModel.

public ObservableCollection<Pin> Locations { get; set; } = new ObservableCollection<Pin>();

And if you add new pin,

Locations.Add(NewLocation());

Each time add a new item in Locations, it will notify the changes and don't have to set a new value to Locations. This will be more convenient.

Hope it works for you.