how to raise event with timer?

Question

ok so i have two classes each with timers set at different intervals. one goes off every 2 seconds, the other every 2 minutes. each time the code runs under the timer i want it to raise an event with the string of data the code generates. then i want to make another class that subscribes to the event args from the other classes and does something like write to console whenever an event is fired. and since one class only fires every 2 minutes this class can store the last event in a private field and reuse that every time until a new event is fired to update that value.

So, how do i raise an event with the string of data?, and how to subscribe to these events and print to screen or something?

this is what i have so far:

    public class Output
    {
        public static void Main()
        {
            //do something with raised events here
        }
    }


    //FIRST TIMER
    public partial class FormWithTimer : EventArgs
    {
        Timer timer = new Timer();

        public FormWithTimer()
        {
            timer = new System.Timers.Timer(200000);

            timer.Elapsed += new ElapsedEventHandler(timer_Tick); // Everytime timer ticks, timer_Tick will be called
            timer.Interval = (200000);            
            timer.Enabled = true;                       // Enable the timer
            timer.Start();                              // Start the timer
        }

      //Runs this code every 2 minutes, for now i just have it running the method        
      //(CheckMail();) of the code but i can easily modify it so it runs the code directly.
        void timer_Tick(object sender, EventArgs e)
        {
            CheckMail();             
        }

        public static string CheckMail()
        {
            string result = "0";

            try
            {
                var url = @"https://gmail.google.com/gmail/feed/atom";
                var USER = "usr";
                var PASS = "pss";

                var encoded = TextToBase64(USER + ":" + PASS);

                var myWebRequest = HttpWebRequest.Create(url);
                myWebRequest.Method = "POST";
                myWebRequest.ContentLength = 0;
                myWebRequest.Headers.Add("Authorization", "Basic " + encoded);

                var response = myWebRequest.GetResponse();
                var stream = response.GetResponseStream();

                XmlReader reader = XmlReader.Create(stream);
                System.Text.StringBuilder gml = new System.Text.StringBuilder();
                while (reader.Read())
                    if (reader.NodeType == XmlNodeType.Element)
                        if (reader.Name == "fullcount")
                        {
                            gml.Append(reader.ReadElementContentAsString()).Append(",");
                        }
                Console.WriteLine(gml.ToString());
           // I want to raise the string gml in an event
            }
            catch (Exception ee) { Console.WriteLine(ee.Message); }
            return result;
        }

        public static string TextToBase64(string sAscii)
        {
            System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
            byte[] bytes = encoding.GetBytes(sAscii);
            return System.Convert.ToBase64String(bytes, 0, bytes.Length);
        }
    }


    //SECOND TIMER
    public partial class FormWithTimer2 : EventArgs
    {
        Timer timer = new Timer();

        public FormWithTimer2()
        {
            timer = new System.Timers.Timer(2000);

            timer.Elapsed += new ElapsedEventHandler(timer_Tick); // Everytime timer ticks, timer_Tick will be called
            timer.Interval = (2000);             // Timer will tick evert 10 seconds
            timer.Enabled = true;                       // Enable the timer
            timer.Start();                              // Start the timer
        }

        //Runs this code every 2 seconds
        void timer_Tick(object sender, EventArgs e)
        {
            using (var file = MemoryMappedFile.OpenExisting("AIDA64_SensorValues"))
        {
            using (var readerz = file.CreateViewAccessor(0, 0))
            {
                var bytes = new byte[194];
                var encoding = Encoding.ASCII;
                readerz.ReadArray<byte>(0, bytes, 0, bytes.Length);

                //File.WriteAllText("C:\\myFile.txt", encoding.GetString(bytes));

                StringReader stringz = new StringReader(encoding.GetString(bytes));

                var readerSettings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };
                using (var reader = XmlReader.Create(stringz, readerSettings))
                {
                    System.Text.StringBuilder aida = new System.Text.StringBuilder();
                    while (reader.Read())
                    {
                        using (var fragmentReader = reader.ReadSubtree())
                        {
                            if (fragmentReader.Read())
                            {
                                reader.ReadToFollowing("value");
                                //Console.WriteLine(reader.ReadElementContentAsString() + ",");
                                aida.Append(reader.ReadElementContentAsString()).Append(",");
                            }
                        }
                    }
                    Console.WriteLine(aida.ToString());
             // I want to raise the string aida in an event
                }
            }
        }
    }

Answer 1

First, I would make a base class that has handles the logic relating to the event. Here is an example:

/// <summary>
/// Inherit from this class and you will get an event that people can subsribe
/// to plus an easy way to raise that event.
/// </summary>
public abstract class BaseClassThatCanRaiseEvent
{
    /// <summary>
    /// This is a custom EventArgs class that exposes a string value
    /// </summary>
    public class StringEventArgs : EventArgs
    {
        public StringEventArgs(string value)
        {
            Value = value;
        }

        public string Value { get; private set; }
    }

    //The event itself that people can subscribe to
    public event EventHandler<StringEventArgs> NewStringAvailable;

    /// <summary>
    /// Helper method that raises the event with the given string
    /// </summary>
    protected void RaiseEvent(string value)
    {
        var e = NewStringAvailable;
        if(e != null)
            e(this, new StringEventArgs(value));
    }
}

That class declares a custom EventArgs class to expose the string value and a helper method for raising the event. Once you update your timers to inherit from that class, you'll be able to do something like:

RaiseEvent(aida.ToString());

You can subscribe to these events like any other event in .Net:

public static void Main()
{
    var timer1 = new FormWithTimer();
    var timer2 = new FormWithTimer2();

    timer1.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);

    //Same for timer2
}

static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
    var theString = e.Value;

    //To something with 'theString' that came from timer 1
    Console.WriteLine("Just got: " + theString);
}