Event Handling C#2.0

Abdul Asif

Hi All,

I am working on a project that requires handling of custom events. Some class will raise the DataEvent of RaiseEventClass. I have to implement event handler for the DataEvent in the RaiseEventClass. Please help me how to implement event handler. Please show some codes if possible.
Below is the skeleton of the class.
Thanks in advance!

public class RaiseEventClass
{
    public delegate void RaiseEventDelegate(ArrayList files);
    public event RaiseEventDelegate DataEvent;


    public void SearchFiles(ArrayList list)
    {
         DataEvent(list); //raising event for testing
    }

}

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Matthew Cochran18y ago
If you just want to bubble an event... after you wire up the event handler as follows....

SerialPort sp = new SerialPort();
sp.DataReceived += sp_DataReceived;

You could just re-fire your own event

void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (null != myEvent)
myEvent(this, EventArgs.Empty);
}

Hope this helps
-Matt
0
Matthew Cochran18y ago
Using any of the async method calls on System.Net.Sockets.Socket, you can fire an event once you recieve the response. Something (very) roughly like:

Socket s = new Socket(AddressFamily.Unknown, SocketType.Stream, ProtocolType.Tcp);

s.BeginReceive(buffers, SocketFlags.None, x =>
{
if (null != myEvent)
myEvent(this, EventArgs.Empty);
}, null);

Of course, you'd have to modify for your application and add exception handling.

0
18y ago
Sorry to butt in on this, but I have a question on this topic as well.

Say I have a Socket, and I want to create an event to be raised when data is received on that socket like the SerialPort.DataReceived event. How could that be achieved?
0
Matthew Cochran18y ago
If you just need to pass different arguments in your event args, try creating a custom EventArgs class to hold the values you want (see below). If you need to pass two items, you can cerate another (EventArgs) class.

Always make sure to make your events private to protect them and expose through the accessors as below. Also, always check the event is not null which happens if there are no subscribers and will throw an exception.

-Matt

public class EventArgs: EventArgs
{
    public EventArgs(T pValue)
    {
        m_value = pValue;
    }

    private T m_value;

    public T Value
    {
      get { return m_value; }
    }
}

public class RaiseEventClass
{

    // protect your events!
   private event EventHandler<EventArgs<ArrayList>> m_DataEvent;

     // public exposure of event
    public event EventHandler<EventArgs<ArrayList>> DataEvent
    {
        add { m_DataEvent += value; }
        remove { m_DataEvent -= value; }
    }

    public void SearchFiles(ArrayList list)
    {
        if (null != m_DataEvent) // always check if null (no subscribers)
            m_DataEvent(this, new EventArgs<ArrayList>(list));
    }
}

0