topic Re: Map.Layers.CollectionChanged event wont fire on layer removal in ArcGIS API for Silverlight Questions

Map.Layers.CollectionChanged event wont fire on layer removal

JudyOgg — Fri, 23 Mar 2012 19:08:20 GMT

The Map.Layers.CollectionChanged event is firing just fine when layers are added to the Map, but not when they are removed. It should.
Has anyone else seen this behaviour (or lack of it)?

Re: Map.Layers.CollectionChanged event wont fire on layer removal

JenniferNery — Fri, 10 Dec 2021 22:04:36 GMT

What version of the API are you using? I could not reproduce with the following code. I have a button click to remove layer from my map.

            MyMap.Layers.CollectionChanged += (a, b) =>
                {
//breakpoint here
                };
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            MyMap.Layers.RemoveAt(MyMap.Layers.Count -1);
        }

Re: Map.Layers.CollectionChanged event wont fire on layer removal

JudyOgg — Fri, 10 Dec 2021 22:04:39 GMT

I'm using version 2.4 of the API, 1.0 of the Viewer, 2.4 of the Extensibility SDK.

Here is my code:

In the ctor of my class:

map.Layers.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Layers_CollectionChanged);

The handler:

void Layers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
                   //some code here            
        }

Re: Map.Layers.CollectionChanged event wont fire on layer removal

DominiqueBroux — Tue, 27 Mar 2012 07:58:43 GMT

It might happen that the layers collection changes after you hook up your handler.
In this case you can suscribe to PropertyChanged event of the map, and hook up your handler if the "Layers" property changed.

Not sure it's your case though, not my 2cts.

Re: Map.Layers.CollectionChanged event wont fire on layer removal

JudyOgg — Tue, 27 Mar 2012 11:10:17 GMT

Thanks! What I ended up hooking up to was the PropertyChanged event of the layers themselves, once I realized that the layers werent always being removed, were just having their visibility set to false.