System.Reflection.EventInfo.RemoveEventHandler C# (CSharp) Method

        public void RemoveEventHandler(Object target, Delegate handler)
        {
            MethodInfo removeMethod = GetRemoveMethod();

            if (removeMethod == null)
                throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_NoPublicRemoveMethod"));

            removeMethod.Invoke(target, new object[] { handler });       
        }
                

            /// <summary>
            /// Remove all the eventhandlers from StateChanged event of original store (<see cref="_store"/>), and return them
            /// as a combined multi cast delegate.
            /// <a href="https://stackoverflow.com/a/16089998/605113">Reference</a>
            /// </summary>
            /// <param name="originalStore"></param>
            /// <returns>Combined Delegate of StateChanged event handlers attached to original store.</returns>
            private Delegate ShiftAllEvents(IStore <TState> originalStore)
            {
                // @ref: https://stackoverflow.com/a/16089998/605113
                Type     theType       = originalStore.GetType();
                Delegate finalDelegate = null;

                //Even though the events are public, the FieldInfo associated with them is private
                foreach (System.Reflection.FieldInfo field in theType.GetTypeInfo().DeclaredFields)
                {
                    //eventInfo will be null if this is a normal field and not an event.
                    System.Reflection.EventInfo eventInfo = theType.GetTypeInfo().GetDeclaredEvent(field.Name);
                    if (eventInfo != null && field.Name == nameof(StateChanged))
                    {
                        MulticastDelegate multicastDelegate = field.GetValue(originalStore) as MulticastDelegate;
                        if (multicastDelegate != null)
                        {
                            List <Delegate> oldHandlers = new List <Delegate>();
                            foreach (Delegate @delegate in multicastDelegate.GetInvocationList())
                            {
                                eventInfo.RemoveEventHandler(originalStore, @delegate);
                                oldHandlers.Add(@delegate);
                            }

                            if (oldHandlers.Count > 0)
                            {
                                finalDelegate = Delegate.Combine(oldHandlers.ToArray());
                            }
                        }
                    }
                }

                return(finalDelegate);
            }