Question

If I initialize a generic dictionary once, and no further adds/updates/removes are allowed, is it safe to have multiple threads reading from it with no locking (assuming that the dictionary is initialized before the readers are started)?

There is a note in the help for the non-generic HashTable that says that it is safe for multiple readers, but I did not see something similar for the Generic Dictionary.

Answer 1

For your future reference, the documentation is here:

http://msdn.microsoft.com/en-us/library/xfhwa508.aspx

It says:

A Dictionary
can support multiple readers
concurrently, as long as the
collection is not modified. Even so,
enumerating through a collection is
intrinsically not a thread-safe
procedure. In the rare case where an
enumeration contends with write
accesses, the collection must be
locked during the entire enumeration.
To allow the collection to be accessed
by multiple threads for reading and
writing, you must implement your own
synchronization.