C# 10 - implementing Lazy Initialization of Concurrent Collections in a Multi-threaded Environment
I'm trying to figure out I'm testing a new approach and Hey everyone, I'm running into an issue that's driving me crazy... I'm working with an scenario with lazy initialization of a `ConcurrentDictionary<TKey, TValue>` in a multi-threaded environment using C# 10. When multiple threads attempt to initialize the same key concurrently, I expected the dictionary to handle it gracefully, but I'm running into `InvalidOperationException` errors due to race conditions. Here’s my implementation: ```csharp using System; using System.Collections.Concurrent; using System.Threading; using System.Threading.Tasks; public class MyClass { private ConcurrentDictionary<int, string> _myDictionary = new ConcurrentDictionary<int, string>(); public string GetOrAdd(int key) { return _myDictionary.GetOrAdd(key, k => InitializeValue(k)); } private string InitializeValue(int key) { // Simulate some complex initialization logic Thread.Sleep(100); return "Value " + key; } } ``` In a stress test where I spawn multiple tasks that call `GetOrAdd` concurrently, I receive exceptions like: ``` InvalidOperationException: Collection was modified; enumeration operation may not execute. ``` I’ve tried wrapping the `GetOrAdd` call in a lock, but that leads to performance optimization and defeats the purpose of using `ConcurrentDictionary`. Is there a proper way to handle this situation without running into exceptions, while still maintaining performance? Any suggestions on best practices or patterns for lazy initialization in concurrent scenarios would be greatly appreciated! My development environment is Linux. How would you solve this? I'm working in a Debian environment. Is this even possible? My team is using C# for this web app. Am I approaching this the right way?