Exclusive lock using key in .NET

Question

I have used the lock statement in C# to exclusively execute a piece of code. Is there a way to do same based on a key.

for e.g.:

lock(object, key)
{
//code-here
}

I have a method which has some piece of code that is not thread-safe, but only if the key (string) happens to be same in two parallel executions. Is there a way to somehow accomplish this in .NET ?

If there is a way then we can have parallel executions if the key being used in the parallel executions is different and could improve performance.

Answer 1

Put lock objects into dictionary indexed by the key - Dictionary<string, object> and grab objects by key to lock.

If you need to dynamically add new key/lock object pairs make sure to lock around the dictionary access, otherwise if after construction you only read values from dictionary no additional locking is needed.

Answer 2

I create a library called AsyncKeyedLock which solves the problem. Internally it uses a ConcurrentDictionary and SemaphoreSlim objects.

In case you're using asynchronous code you can use:

using (await _locker.LockAsync(myObject.Id))
{
   ...
}

or if you're using synchronous code:

using (_locker.Lock(myObject.Id))
{
   ...
}