CODEWITHSUNDEEP
c#.netmultithreading.net-core
Hourglass
Hourglass

Reputation: 172

is there any implement of CallContext.GetData / SetData in .NET Core?

AsyncLocal<> in .NET Core like CallContext.LogicGetData/LogicSetData. How about GetData and SetData?
Thread.GetData/SetData, ThreadStatic, ThreadLocal all of these has same problem, when Thread finish, these value will not clean, and if these Thread reuse(or maybe Thread Id reuse), the LocalValue is already exists. 

class Program
{
    [ThreadStatic]
    private static string Static;
    private static ThreadLocal<string> Local = new ThreadLocal<string>(false);
    private static LocalDataStoreSlot Slot = Thread.AllocateDataSlot();

    static void Main(string[] args)
    {
        var threadIds = new List<int>();
        for (var i = 0; i < 100; i++)
        {
            Task.Run(() =>
            {
                if (threadIds.Contains(Thread.CurrentThread.ManagedThreadId))
                {
                    if(Static == null || Local.Value == null || Thread.GetData(Slot) == null)
                    {
                        // never get in
                    }
                    else
                    {
                        // same thread id always already exists value
                    }
                }
                else
                {
                    threadIds.Add(Thread.CurrentThread.ManagedThreadId);
                    if (Static == null && Local.Value == null && Thread.GetData(Slot) == null)
                    {
                        var threadId = Thread.CurrentThread.ManagedThreadId.ToString();
                        Static = threadId;
                        Local.Value = threadId;
                        Thread.SetData(Slot, threadId);
                    }
                    else
                    {
                        //never get in
                    }
                }
            }).Wait();
        }

        Console.WriteLine("Press any key to continue...");
        Console.ReadKey();
    }
}

I know how CallContext do, it just copy LogicalCallContext values to child thread and do not copy IllogicalCallContext. But .NET Core only IAsyncLocalValueMap in ExecutionContext, and it always copy to child thread(except SuppressFlow). So, is there any implement of GetData/SetData? or any way to clean ThreadLocal when its finished.

Upvotes: 5

Views: 2801

Answers (1)

Ben Adams
Ben Adams

Reputation: 3431

Use a change handler for the AsyncLocal to clear the value when the thread changes?

private static AsyncLocal<string> AsyncLocal
    = new AsyncLocal<string>(ThreadContextChanged);

private static void ThreadContextChanged(AsyncLocalValueChangedArgs<string> changedArgs)
{
    if (changedArgs.ThreadContextChanged &&
        changedArgs.CurrentValue != null)
    {
        AsyncLocal.Value = null;
    }
}

Upvotes: 2

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