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Immutability and static variables

I am developing some immutable classes, but I have some variables like say .Count

to have the total number of instances. But will a static variable affect multithreading?

Because methods like Add, Remove, etc. need to update the value .Count

. Maybe I should make this a lazy property?

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If you are just doing a counter, blocked operations can be an option, not a blocking. MSDN has a good example of this in the context of reference counting.



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You might want to consider the functions from the Interlocked class, at least in the example you provided.



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But will a static variable affect multithreading?

exactly! the shared state is influenced, by refutation, by multithreading.

Because methods like Add, Remove, etc. have to update the .Count value. Maybe I should make this a lazy property?

it's better to use a class that does atomic add (like AtomicInteger in java) to avoid blocking: look here

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Yes, whenever you update a shared variable in a multithreaded environment, you just need to wrap those updates in a lock.

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