6 Answers, 1 is accepted
It is a known problem with using of the Clear method. We've fixed this problem already. We added new method RemoveAll to the providers collection. It should be used instead of Clear method. The fix will be available in the 2011.SP1 which will be available soon.
the Telerik team
Bringing this one back. I am not currently subscribed so my last source code is Dec 2014. However the problem still exists even though this problem was found back in 2011.
Clear calls OnCollectionChanged with Reset and null for the oldItems.
RadMap.ProvidersCollectionChanged is checking for oldItems of not null, so Clear does not have the proper effect. Calling Remove on each provider works fine.
There is no RemoveAll listed in the MapProviderCollection.
The RemoveAll method mentioned by Andrey Murzov is actually an IList extension method residing in Telerik.Windows.Controls.Map.
So probably you only need to add the namespace with using in the top section of your file.