Mastering C# Concurrency

ConcurrentDictionary

We can improve the implementation of CustomProvider using ConcurrentDictionary<TKey, TValue> to handle the synchronization:

public class CustomProvider
{
    private readonly 
        ConcurrentDictionary<string, OperationResult> _cache = 
            new ConcurrentDictionary<string, OperationResult>();
 
    public OperationResult RunOperationOrGetFromCache(
        string operationId)
    {
        return _cache.GetOrAdd(operationId, 
            id => RunLongRunningOperation(id));
    }
 
    private OperationResult RunLongRunningOperation(
        string operationId)
    {
        // Running real long-running operation
        // ...
        Console.WriteLine("Running long-running operation");
        return OperationResult.Create(operationId);
    }
}

The code became much simpler. We just used the GetOrAdd method and it does exactly what we ...