AggregateException.Flatten Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Flattens AggregateException instances into a single, new instance.
Assembly: mscorlib (in mscorlib.dll)
If any inner exceptions are themselves instances of AggregateException, this method will recursively flatten all of them. The inner exceptions returned in the new AggregateException will be the union of all of the inner exceptions from the exception tree rooted at the provided AggregateException instance.