Dictionary<TKey, TValue>.ICollection.IsSynchronized Property
Gets a value indicating whether access to the ICollection is synchronized (thread safe).
Assemblies: mscorlib (in mscorlib.dll)
System.Collections (in System.Collections.dll)
Property ValueType: System.Boolean
true if access to the ICollection is synchronized (thread safe); otherwise, false. In the default implementation of Dictionary<TKey, TValue>, this property always returns false.
Default implementations of collections in the System.Collections.Generic namespace are not synchronized.
Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which can cause the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.
Getting the value of this property is an O(1) operation.