FieldDelegator

FieldDelegator.cs

public class FieldDelegator<T> : FieldDelegator where T : Delegate
{
    public FieldDelegator(FieldInfo field, object owner = null) : base(field, owner) { }

    public static void Do(FieldInfo fld, object owner = null, T del = null, bool combine = true) =>
        FieldDelegator.Do(fld, owner, del, combine);
    public void Do(T del, bool combine = true) => Do(Instance, Owner, del, combine);
}
public class FieldDelegator
{
    public FieldDelegator(FieldInfo field, object owner = null)
    {
        Instance = field;
        Owner = owner;
    }
    protected FieldInfo Instance;
    protected object Owner;
    public static Delegate ConvertDelegate(Type convertTo, Delegate del) => Delegate.CreateDelegate(convertTo, del.Target, del.Method);
    public delegate Delegate? DelegateAction(Delegate? a, Delegate? b);

    public static void Do(FieldInfo fld, object owner = null, Delegate? del = null, bool combine = true) =>
        fld.SetValue(owner, (combine ? (DelegateAction)Delegate.Combine : Delegate.Remove)
            (fld.GetValue(owner) as Delegate, ConvertDelegate(fld.FieldType, del)));
    public void Do(Delegate del, bool combine = true) => Do(Instance, Owner, del, combine);

    public static object Invoke(FieldInfo fld, object owner = null, params object[] args) =>
        (fld.GetValue(owner) as Delegate)?.DynamicInvoke(args);
    public object Invoke(params object[] args) => Invoke(Instance, Owner, args);
    public static T Invoke<T>(FieldInfo fld, object owner = null, params object[] args) =>
        (T)Invoke(fld, owner, args);
    public object Invoke<T>(params object[] args) => Invoke<T>(Instance, Owner, args);
}

class Program
{
  static void Main()
  {
      var a = new A();
      var fld = typeof(A).GetField(nameof(A._e));
      var delegator = new FieldDelegator<MyAction>(fld, a);
      delegator.Do(SomeAction1);
      delegator.Do(SomeAction2);
      delegator.Invoke();
      delegator.Do(SomeAction1, false);
      delegator.Do(SomeAction2, false);
      delegator.Invoke();
  }
}