Just like in Web User Control, we can raise Events which can be handledby pages or other controls that 'listens' in on the event, can the samebe accomlished in JS?
The Web User Control shouldnt know who has registered to listen in onthe event but somehow the Control has to communicate that something hashappened.Would any of the below code help in what I want to accomplish?Basically different components can listen in or another componentsevents, and when that event is raised, each of the listeners methodsare invoked?
Type.createEnum('Sys.ActionSequence','BeforeEventHandler', 0,'AfterEventHandler', 1);
Sys.IAction = function() {
this.get_sequence = Function.abstractMethod;
this.execute = Function.abstractMethod;
this.setOwner = Function.abstractMethod;
}
Sys.IAction.registerInterface('Sys.IAction');Type.Event = function(owner, autoInvoke) {
var _owner = owner;
var _handlers =null;
var _actions =null;
var _autoInvoke = autoInvoke;
var _invoked =false;this.get_autoInvoke = function() {
return _autoInvoke;
}this._getActions = function() {
if (_actions && _actions.length && !_owner)throw"Actions are only supported on events that have an owner.";
if (_actions ==null) {
_actions = [];
}
return _actions;
}
this._getHandlers = function() {
if (_handlers ==null) {
_handlers = [];
}
return _handlers;
}
this._getOwner = function() {
return _owner;
}this.isActive = function() {
return ((_handlers !=null) && (_handlers.length != 0)) ||
((_actions !=null) && (_actions.length != 0));
}this.get_isInvoked = function() {
return _invoked;
}this.dispose = function() {
if (_handlers) {
for (var h = _handlers.length - 1; h >= 0; h--) {
_handlers[h] =null;
}
_handlers =null;
}
if (_actions) {
for (var i = _actions.length - 1; i >= 0; i--) {
_actions[i].dispose();
}
_actions =null;
}_owner =null;
}this._setInvoked = function(value) {
_invoked =true;
}
}
Type.Event.registerSealedClass('Type.Event',null, Sys.IDisposable);Type.Event.prototype.add = function(handler) {
this._getHandlers().add(handler);
if (this.get_autoInvoke() &&this.get_isInvoked()) {
handler(this._getOwner(),null);
}
}
Type.Event.prototype.addAction = function(action) {
action.setOwner(this._getOwner());
this._getActions().add(action);
}
Type.Event.prototype.remove = function(handler) {
this._getHandlers().remove(handler);
}
Type.Event.prototype.removeAction = function(action) {
action.dispose();
this._getActions().remove(action);
}
Type.Event.prototype.invoke = function(sender, eventArgs) {
if (this.isActive()) {
var actions =this._getActions();
var handlers =this._getHandlers();
var hasPostActions =false;
var i;for (i = 0; i < actions.length; i++) {
if (actions[i].get_sequence() == Sys.ActionSequence.BeforeEventHandler) {
actions[i].execute(sender, eventArgs);
}
else {
hasPostActions =true;
}
}for (i = 0; i < handlers.length; i++) {
handlers[i](sender, eventArgs);
}if (hasPostActions) {
for (i = 0; i < actions.length; i++) {
if (actions[i].get_sequence() == Sys.ActionSequence.AfterEventHandler) {
actions[i].execute(sender, eventArgs);
}
}
}this._setInvoked();
}
}
Sorry for the message, I forgot to check the Atlas Client sidereference library where it has a nice page on this:http://atlas.asp.net/docs/Client/Type/Event/default.aspx
but anyone with more concrete examples would be much appreciated :)
Hi,
the Atlas framework gives you the ability to declare multiple handlers for an event. Just use the add() method on the exposed event to add a handler.
For example, if the instance myObject exposes a myevent event, you can write a statement like:
myObject.myevent.add(myMethod);
to register a handler for that event.
Thanks for your response Garbin (+ props to your weblog)
Looking at your pager example:
// Events.td.addEvent('pageChanged',true);
// The Pager exposes the pageChanged event, which is raised
// when the page index to be displayed changes.
this.pageChanged =this.createEvent();
...Which exposes a pageChanged property where I can pass in one method on the initialization of the Atlas Control.
...
The event is raised by:
this.pageChanged.invoke(this,new AtlasNotes.PagerEventArgs(_pageIndex, _pageSize, _totalRecords));so going by your post, I can append more methods to be handled by going:
myObject.pageChanged.add(myMethod);
If so, Ill try it on Monday :D
The above code works beautifully :)
