creating another component in the component's initialize method

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creating another component in the component's initialize method

Last post 10-16-2007 10:59 PM by null12345. 4 replies.

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creating another component in the component's initialize method

10-16-2007, 1:08 PM

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12 point Member
null12345
Member since 07-21-2007, 12:35 PM
Posts 38

I'm trying to create another component in the component's initialize method.

When I create the component in the pageLoad stage, it works fine. But If I create the component in the Init stage, the second component's initialize method doesn't get callled.

Here's the codes.

Type.registerNamespace('Samples');

Samples.MyComponent1 = function() {
	Samples.MyComponent1.initializeBase(this);
}

Samples.MyComponent1.prototype = {
	initialize : function() {
		Samples.MyComponent1.callBaseMethod(this, 'initialize');

		$create(Samples.MyComponent2, {}, {}, {});

		alert(Object.getTypeName(this) + " get initialized!");
	},

	dispose : function() {
		alert(Object.getTypeName(this) + " get disposed!");
		Samples.MyComponent1.callBaseMethod(this, 'dispose');
	}
}

Samples.MyComponent1.registerClass('Samples.MyComponent1', Sys.Component);

Samples.MyComponent2 = function() {
	Samples.MyComponent2.initializeBase(this);
}

Samples.MyComponent2.prototype = {
	initialize : function() {
		Samples.MyComponent2.callBaseMethod(this, 'initialize');
		alert(Object.getTypeName(this) + " get initialized!");
	},

	dispose : function() {
		alert(Object.getTypeName(this) + " get disposed!");
		Samples.MyComponent2.callBaseMethod(this, 'dispose');
	}
}

Samples.MyComponent2.registerClass('Samples.MyComponent2', Sys.Component);

if (typeof(Sys) !== 'undefined') Sys.Application.notifyScriptLoaded();

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
		<asp:ScriptManager ID="ScriptManager1" runat="server" >
			<Scripts>
				<asp:ScriptReference Path="~/scripts/Test.js" />
			</Scripts>
		</asp:ScriptManager>

    <script type="text/javascript">

	Sys.Application.add_init(pageInit);

	function pageInit() {
		$create(Samples.MyComponent1, {}, {}, {}, null);
	}

	function pageLoad() {
	}

    </script>
    </div>
    </form>
</body>
</html>

Re: creating another component in the component's initialize method

10-16-2007, 3:44 PM

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Answer

25,662 point All-Star
Luis Abreu
Member since 02-12-2005, 6:22 AM
Madeira [Portugal]
Posts 5,368

hello.

this is something that i have never done. generally, i'd create the control outside and pass it as reference to the top control (but again, you might have a requirement which makes this impossible). if you look at the Sys$_Application$endCreateComponents you'll see why you're not getting the call. here's the code for that method:

function Sys$_Application$endCreateComponents() {
    var components = this._secondPassComponents;
    for (var i = 0, l = components.length; i < l; i++) {
        var component = components[i].component;
        Sys$Component$_setReferences(component, components[i].references);
        component.endUpdate();
    }
    this._secondPassComponents = [];
    this._creatingComponents = false;
}

when you get the initialization part of the for, components' length is set to 1 since you only have one component. during the 1st step of the cycle, you'll get a new component added to that collection. unfortunately, the above code will always be false and the initialize of the second component won't be called.

--
Regards,
Luis Abreu
email: labreu_at_gmail.com
EN blog:http://msmvps.com/blogs/luisabreu

Re: creating another component in the component's initialize method

10-16-2007, 5:05 PM

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14,010 point Star
bleroy
Member since 04-12-2003, 7:09 AM
Redmond
Posts 2,296

Luis is right, $create is only intended as a shortcut for page developers and as something that server-side components use to instantiate themselves from in-page code. Component developers writing client-side code should just new up the component and initialize it "by hand".

$create has this two pass model that hides the complexities of creating components that refer to each other. For code inside a component, there is no need for such a model.

Also, in production code, you'd assign the created component to a member field so that you can properly dispose of it from the dispose of your primary component.

Bertrand
----
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