SyncLock on SyncRoot

Question

I have created a synchronized queue and am using SyncLock on the SyncRoot property of that queue when I invoke the Enqueue/Dequeue methods. The methods are invoked from instances of standard producer/consumer classes.

Is that a proper use of the SyncRoot property?

Would it be better practice to create a private shared object in each class and lock on that instead?

Please explain your reasoning.

Answer 1

Yes, that's exactly what the SyncRoot property is for. In particular, it means that if another "wrapper" collection is created, it will probably use the same SyncRoot, so everyone can still synchronize correctly.

You could create your own lock object, and that would make absolutely sure that no-one else locked at the same time - but it would also mean that other code couldn't safely work with the same collection. It really depends on the scenario - is other code able to use the same collection? Is that other code under your control?

Note that you should take out a lock for all operations, not just Enqueue/Dequeue. In particular, if you want to iterate over the collection you should hold the lock for that whole time, as a change in the middle will invalidate the iterator.