Threadsafe foreach enumeration of lists

Question

I need to enumerate though generic IList<> of objects. The contents of the list may change, as in being added or removed by other threads, and this will kill my enumeration with a "Collection was modified; enumeration operation may not execute."

What is a good way of doing threadsafe foreach on a IList<>? prefferably without cloning the entire list. It is not possible to clone the actual objects referenced by the list.

Answer 1

ICollection MyCollection;
// Instantiate and populate the collection
lock(MyCollection.SyncRoot) {
  // Some operation on the collection, which is now thread safe.
}

From MSDN

Answer 2

There is no such operation. The best you can do is

lock(collection){
    foreach (object o in collection){
       ...
    }
}