[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Checks for reentrant attempts to change this collection.
Assembly: System (in System.dll)
If there was a call to BlockReentrancy of which the IDisposable return value has not yet been disposed of. Typically, this means when there are additional attempts to change this collection during a CollectionChanged event. However, it depends on when derived classes choose to call BlockReentrancy.