How to raise events defined using Event Properties

Question

I am learning Events and Delegates & started with multiple events now. Just that the docs does not supply any information or code example to raising events defined in this manner.Below you can find a simple example

Sample Code

public class Person
    {
        private string _name;
        private string _phone;

        public string Name
        {
            get { return _name; }
            set
            {
                _name = value;
            }
        }

        public string Phone
        {
            get { return _phone; }
            set
            {
                _phone = value;
            }
        }

        protected EventHandlerList EventDelegateCollection = new EventHandlerList();

        //define the event key
        static readonly object PhoneChangedEventKey = new object();
        public event EventHandler PhoneChanged
        {
            add
            {
                EventDelegateCollection.AddHandler(PhoneChangedEventKey, value);
            }
            remove
            {
                EventDelegateCollection.RemoveHandler(PhoneChangedEventKey, value);
            }
        }
    }

I would like to raise the event when the Phone number is set. if anything sounds funky and don't understand what i am talking about see here

Update

I would like to clear some doubts here. There are Two ways you can actually subscribe and invoke the event handlers the classical pattern(as described here) where the steps are

Define the delegate that acts as signature for subscribed methods.
Define the Event that delegates
Define the method that raises the handlers note: above method creates field for every event hence consumes more memory reference

Event Property is another way where you do below

Define a object that acts as Key to a event
Define a method to add and remove handlers for the event from the event invocation list
Raise the event by determining event handlers based on event key

This MSDN link describes raising the event: http://msdn.microsoft.com/en-us/library/9aackb16%28v=VS.80%29.aspx — H H, Oct 15 '11 at 06:19
possible duplicate of [How to dispatch events in C#](http://stackoverflow.com/questions/2448487/how-to-dispatch-events-in-c-sharp) — H H, Oct 15 '11 at 06:20
@HenkHolterman i repeat that is classical way to invoke event handlers, Event Properties is another way look here http://msdn.microsoft.com/en-us/library/8843a9ch.aspx — Deeptechtons, Oct 15 '11 at 06:23
That page also lists the `OnMouseDown()` and `OnMouseUp()` methods so what is your exact question then? — H H, Oct 15 '11 at 06:27
@HenkHolterman thank you, solved the question myself and code is available below. — Deeptechtons, Oct 15 '11 at 06:29
@Anyone who wanted to close the question, please see the update of why this question differs from other related questions — Deeptechtons, Oct 15 '11 at 06:40

score 4 · Accepted Answer · edited Jun 20 '20 at 09:12

This is how you should actually raise it

Code

public class Person
{
    private string _name;
    private string _phone;

    public string Name
    {
        get { return _name; }
        set
        {
            _name = value;
        }
    }

    public string Phone
    {
        get { return _phone; }
        set
        {
            _phone = value;
            //Invoke the Handlers now
            OnPhoneChanged();
        }
    }

    protected EventHandlerList EventDelegateCollection = new EventHandlerList();
    static readonly object PhoneChangedEventKey = new object();
    public event EventHandler PhoneChanged
    {
        add
        {
            EventDelegateCollection.AddHandler(PhoneChangedEventKey, value);
        }
        remove
        {
            EventDelegateCollection.RemoveHandler(PhoneChangedEventKey, value);
        }
    }

    private void OnPhoneChanged()
    {
        EventHandler subscribedDelegates = (EventHandler)this.EventDelegateCollection[PhoneChangedEventKey];
        subscribedDelegates(this, EventArgs.Empty);
    }
}

score -1 · Answer 2 · answered Oct 15 '11 at 06:23

I suggest you to read Delegates and Events in C#. The code below is what you want.

public class Person
{
    public event EventHandler<string> PhoneNumberChanged;

    private string _name;
    private string _phone;

    public string Name
    {
        get { return _name; }
        set
        {
            _name = value;
        }
    }

    public string Phone
    {
        get { return _phone; }
        set
        {
            _phone = value;

            if (this.PhoneNumberChanged != null)
            {
                this.PhoneNumberChanged(this._phone);
            }
        }
    }
}

How to raise events defined using Event Properties

Sample Code

Update

2 Answers2

Code