C# - Trouble with Concurrent Access to a Dictionary in a Multi-threaded Environment
I've looked through the documentation and I'm still confused about I'm building a feature where I'm working on a C# application that processes data asynchronously and uses a `Dictionary<TKey, TValue>` to store intermediate results. However, I'm working with issues when multiple threads try to read from and write to the dictionary simultaneously, leading to `InvalidOperationException`. Here’s a simplified version of my approach: ```csharp using System; using System.Collections.Generic; using System.Threading.Tasks; class Program { private static Dictionary<int, string> _dataStore = new Dictionary<int, string>(); private static object _lock = new object(); static async Task Main(string[] args) { var tasks = new List<Task>(); for (int i = 0; i < 10; i++) { tasks.Add(Task.Run(() => WriteToDictionary(i, $"Value {i}"))); tasks.Add(Task.Run(() => ReadFromDictionary(i))); } await Task.WhenAll(tasks); } private static void WriteToDictionary(int key, string value) { lock (_lock) { _dataStore[key] = value; } } private static void ReadFromDictionary(int key) { lock (_lock) { if (_dataStore.TryGetValue(key, out string value)) { Console.WriteLine(value); } } } } ``` Although I wrapped my access to the dictionary in a `lock` statement, I still receive occasional `InvalidOperationException` errors, which seem to stem from cases where the dictionary is being modified while being read. I've tried using `ConcurrentDictionary` instead, but I still need to maintain order in the keys and want to use it directly. Is there a better approach to handle concurrent read and write access to a dictionary while ensuring that the order of keys is preserved in C#? Any advice on best practices or design patterns would be greatly appreciated! Am I approaching this the right way? For context: I'm using C# on Linux. I'd really appreciate any guidance on this.