Question

I have the following line in C#:

_timer.ElapsedTick += _somefunction1;
_timer.ElapsedTick += _somefunction2;
_timer.ElapsedTick += _somefunction3;

How to invoke all methods subscribed to _timer.ElapsedTick without specifying the _somefunction ? Somewhere along this pseudo-line

invoke(_timer.ElapsedTick);

Answer 1

Can it be done using conventional C#? No (as previously stated). But using reflection it is possible. Here is some tested code based on the answer to this MSDN forum thread:

class InvokeFromMe
{
    public event EventHandler RaiseMe;
}

class Program
{
    static void Main(string[] args)
    {
        var fromMe = new InvokeFromMe();

        fromMe.RaiseMe += fromMe_RaiseMe;
        fromMe.RaiseMe += fromMe_RaiseMe1;
        fromMe.RaiseMe += fromMe_RaiseMe2;

        FireEvent(fromMe, "RaiseMe", null, EventArgs.Empty);
    }

    static void fromMe_RaiseMe(object sender, EventArgs e)
    {
        Console.WriteLine("Event Handler 0 Raised");
    }
    static void fromMe_RaiseMe1(object sender, EventArgs e)
    {
        Console.WriteLine("Event Handler 1 Raised");
    }
    static void fromMe_RaiseMe2(object sender, EventArgs e)
    {
        Console.WriteLine("Event Handler 2 Raised");
    }

    public static void FireEvent(object onMe, string invokeMe, params object[] eventParams)
    {
        MulticastDelegate eventDelagate =
              (MulticastDelegate)onMe.GetType().GetField(invokeMe,
               System.Reflection.BindingFlags.Instance |
               System.Reflection.BindingFlags.NonPublic).GetValue(onMe);

        Delegate[] delegates = eventDelagate.GetInvocationList();

        foreach (Delegate dlg in delegates)
        {
            dlg.Method.Invoke(dlg.Target, eventParams);
        }
    } 

}

UPDATE

I’m not familiar with the System.Timer.Timer class, so I’m not sure what is different from my provided example. You could perhaps try something like:

public static void FirePublicEvent(object onMe, string invokeMe, params object[] eventParams)
{
    MulticastDelegate eventDelagate =
          (MulticastDelegate)onMe.GetType().GetField(invokeMe,
           System.Reflection.BindingFlags.Instance |
           System.Reflection.BindingFlags.Public).GetValue(onMe);

    Delegate[] delegates = eventDelagate.GetInvocationList();

    foreach (Delegate dlg in delegates)
    {
       dlg.Method.Invoke(dlg.Target, eventParams);
    }
}