Question

It it possible to retrive who is subscribing to a event in C#?

example

class MyClass
{
  public string Name { get; set; } 
}

class Syncronizer
{
  public delegate void SynchronizatonEventHandler(MyClass myClass);
  public event SynchronizatonEventHandler OnSyncFinished;
}

If i have something like that is it possible for me to see/use the myClass.Name string and use it for logging when the event is subscribed to?

What i want to accomplish is that i want to log every subscribe and unsubscribe from my Syncronizer class.

Answer 1

Here’s a working example:

class Syncronizer
{
    public delegate void SynchronizatonEventHandler(MyClass myClass);
    private event SynchronizatonEventHandler onSyncFinished;
    public event SynchronizatonEventHandler OnSyncFinished
    {
        add
        {
            var method = new StackTrace().GetFrame(1).GetMethod();
            Console.WriteLine("{0}.{1} subscribing", method.ReflectedType.Name, method.Name);
            onSyncFinished += value;
        }
        remove
        {
            var method = new StackTrace().GetFrame(1).GetMethod();
            Console.WriteLine("{0}.{1} unsubscribing", method.ReflectedType.Name, method.Name);
            onSyncFinished -= value;
        }
    }
}

Note that you can not log myClass.Name, since that doesn’t exist in the add and remove procedures. I have it logging (to Console.WriteLine) the class and method that subscribed to the event, which is, I think, what you were after.