TraceListener and writing to a listbox with EventHandler

So say you want to have a Trace listener setup to listen for any Trace outputs and you would like to take the Trace Write outputs and put that into a listbox.

This shows you how to setup a custom eventargs, custom TraceListner and then add the custom Trace listener to add messages received to a listbox.

Make a new custom EventArgs like this:

[code:c#]    public class EventListenerArgs : EventArgs
    {
        private string _message;

        public string Message

        {
            get { return _message; }
            set { _message = value; }
        }

        public EventListenerArgs(string Message)
        {
            this.Message = Message;
        }
    }[/code]

Then setup a custom TraceListner that implements the EventListener above like this;

[code:c#]    public class EventFiringListener : TraceListener
    {
        public event EventHandler<EventListenerArgs> WriteEvent;

        public override void WriteLine(string message)
        {
            EventHandler<EventListenerArgs> temp = WriteEvent;
            if (temp != null)
            {
                temp(this, new EventListenerArgs(message));
            }

        }

        public override void Write(string s)
        {
            EventHandler<EventListenerArgs> temp = WriteEvent;
            if (temp != null)
            {
                temp(this, new EventListenerArgs(s));
            }

        }          
    }

[/code]

Then in your form (where you have the listbox) create the custom TraceListener and add it to the TraceListener collections;

[code:c#]

EventFiringListener listener = new EventFiringListener();
listener.WriteEvent += new EventHandler<EventListenerArgs>(listener_WriteEvent);[/code]

And the method event could look like this;

[code:c#]        void listener_WriteEvent(object sender, EventListenerArgs e)
{
        this.listbox.items.add(e.Message);

}
[/code]

Enjoy!

0