CODEWITHSUNDEEP
c#.netmultithreading
qkhanhpro
qkhanhpro

Reputation: 5220

Refactoring Dictionary into ConcurrentDictionary

Currently I have some async methods that all trying to update and read from a Dictionary

Side question: Can the async functions cause KeyNotFoundException and NullReferenceException? I am just doing _dictonary[myString] = myObject

Anyways. I would like to replace all Dictionary<string,object> with ConcurrentDictionary<string, object> . I don't care at all whether some thread get the data right before/after another thread write into it.

Is there any trouble I can get into if I just do a text replace all Dictionary with ConcurrentDictionary and it compiles successfully?

Upvotes: 0

Views: 50

Answers (1)

ProgrammingLlama
ProgrammingLlama

Reputation: 38727

Internally ConcurrentDictionary's indexer method uses TryGetValue and the same TryAddInternal as TryAdd does.

Setting a value shouldn't throw an exception unless your key is null. It should work as you expect (although another thread could come in and change it before you read it again).

You will still get a KeyNotFoundException if the key isn't found in the dictionary. There could be timing issues if you expect one thread to insert a value, and then you try and read it using concurrentDictionary[key]. I'd recommend using TryGetValue if you want safety in this respect.

Upvotes: 2

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