Question

How can I get reference to the task my code is executed within?

ISomeInterface impl = new SomeImplementation();
Task.Factory.StartNew(() => impl.MethodFromSomeInterface(), new MyState());

...

void MethodFromSomeInterface()
{
    Task currentTask = Task.GetCurrentTask();    // No such method?
    MyState state = (MyState) currentTask.AsyncState();
}

Since I’m calling some interface method, I can’t just pass the newly created task as an additional parameter.

Answer 1

Since you can’t change the interface nor the implementation, you’ll have to do it yourself, e.g., using ThreadStaticAttribute:

static class SomeInterfaceTask
{
  [ThreadStatic]
  static Task Current { get; set; }
}

...

ISomeInterface impl = new SomeImplementation();
Task task = null;
task = Task.Factory.StartNew(() =>
{
  SomeInterfaceTask.Current = task;
  impl.MethodFromSomeInterface();
}, new MyState());

...

void MethodFromSomeInterface()
{
  Task currentTask = SomeInterfaceTask.Current;
  MyState state = (MyState) currentTask.AsyncState();
}