Events

Events

• justin tighe

  create an event to do an event to raise an event.

  or something like that.... :-P

  This is good stuff.

  Cheers!

  
  
  

• DmitryMS

  public delegate void Whatever();

  public static event Whatever MyEvent;

  
  
  

• dron747

  Yes...good point.

  I treat it like any static definition....use when only one "instance" will be needed.

  That said...I remove the wiring each time it fires in the form.....just get rid of the subscription every time.

  
  
  

• Gagand

  I looked at that... Can you show us how a static delegate instance can invoke a method on a form instance I'd like to do it but don't know how...
  
  
  
  

• Roger_Melb

  Let me recap:

  FormA creates ObjectB

  ObjectB creates ObjectC

  ObjectC fires an Event.

  You want FormA to receive that event.

  Unless FormA has some knowledge about ObjectC, this is impossible.

  What you can do, is have ObjectB receive the event, and in response, fire a similar event. Then all you need do is have FormA subscribe to the event from ObjectB.

  
  
  

• chirag.dave

  sorry but can you give me an example on how YOU would do it

  more specifically how would i subscribe to the event from the class (not main form) which the main form knows nothing about, and vica versa

  
  
  

• DJ Pandamonium

  thanks, I was wondering how it would be possible.

  That should do it, a better understanding now!

  
  
  

• sjb31988

  lol...once I figured it out I went event crazy for a while.

  beware tho, static haters are everywhere.

  
  
  

• Daikoku

  yeh thats pretty much what im trying to achieve and also making sure its all best practice.

  sorry, im just a "best practice" freak

   

  I guess you could, as suggested/hinted, just perhaps raise it going "up" the way (from one class to the other to the other....etc...) but wondering if this is a valid design

  
  
  

• R.Tutus

  Do it exactly the same way...

  Create the event in the class.

  Subscribe to the event in the form.

  Fire the event anywhere in the class.

  
  
  

• Muhammad Akhtar Shiekh

  using System;

  using System.Collections.Generic;

  using System.Text;

  namespace WindowsApplication1

  {

  class EventClass

  {

  public delegate void MakeFormDoSomething();

  public static event MakeFormDoSomething FireEvent;

  public static void RaiseEvent()

  {

  FireEvent();

  }

  }

  }

  //FORM:

  private void Form1_Load(object sender, EventArgs e)

  {

  EventClass.FireEvent += new EventClass.MakeFormDoSomething(EventClass_FireEvent);

  EventClass.RaiseEvent();

  }

  void EventClass_FireEvent()

  {

  MessageBox.Show("Form has recieved event");

  }

  
  
  

• Enes Kabacaoglu

  Thanks a million, it fought me tooth-and-nail to convert this to legal VB.NET syntax but I got it. Me like, me like a lot. This opens up a lot of new possibilities...
  
  
  
  

• cunha

  Ignore them, it solves a real problem. It they get upset about "static", they don't get it. Again, thanks! Now, how am I going to not let it slip out of control... I don't see anything wrong with the approach, as long as the class uses RemoveHandler when it gets disposed... Hmm, that puts a bit of pressure on properly dealing with Dispose(). What is your experience
  
  
  
  

• StarsFire

  Let's keep it simple: Form1 creates a Class1 object. Class1 in turn creates a Class2 object. Two ways I can think of:
  
  #1: Class2 object has a reference to the Class1 object, passed to it by the constructor or a method: add a method to Class1 that raises the event, Class2 calls this method.
  
  #2: Class1 has a reference to the Class2 object, it should because it created it: Class2 raises an event that Class1 catches, then in turn it raises its own event.
  
  You could also handle case #2 by passing Class2 an initialized delegate instance but that is really no different from case #1.
  
  
  
  
• Events