Question

If I have the below code, should I just call the Action or should it call Action.Invoke?

public class ClassA
{
  public event Action<string> OnAdd;

  private void SomethingHappened()
  {
    if (OnAdd != null)
     OnAdd("It Happened"); //Should it be OnAdd.Invoke("It Happened") ???????
  }
}

public class ClassB
{

  public ClassB()
  {
    var myClass = new ClassA();
    myClass.OnAdd += Add;
  }

  private void Add(string Input)
  {
    //do something
  }  
}

Answer 1

The two are equivalent, the compiler converts OnAdd("It Happened"); into OnAdd.Invoke("It Happened"); for you.

I guess it’s a matter of preference, however I personally prefer the terser form.

As an aside, it is generally preferable to take a local copy of a class level delegate before invoking it to avoid a race condition whereby OnAdd is not null at the time that it is checked, but is at the time that it is invoked:

private void SomethingHappened()
{
  Action<string> local = OnAdd;
  if (local != null)
  {
    local("It Happened");
  }
}