Assembly: mscorlib (in mscorlib.dll)
Default implementations of collections in System.Collections.Generic are not synchronized.
Enumerating through a collection is intrinsically not a thread-safe procedure. To guarantee thread safety during enumeration, you can lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.
Retrieving the value of this property is an O(1) operation.