Great tutorial but I am getting an error on compilation.  In the bottom left corner of the browser it says "error on page" in the details section it says "DisabledButton is undefined at line 60".  This is in the $create command.  Any idea why this might be happening?  any help would be much appreciated.

it is realy helpful tutorial ,but i have problem with the method return GetPropertyValue("TargetButtonID", "");

the errer messsage is

the name GetPropertyValue does not exist in the current context

can any body help in that .

Great video, I am interested in more videos of extender. can you please send more detail on ajax extender.

Thanks

I do hope I get answers to my Question here as I am cluesless as to what it is I have not been doing right here. I have watched this particular video at least 5 times and I still can not seem to get my own AJAX extender control to work as I expect it to. I have posted this same on the forum and still no responses so I figure, I might try to ask you directly.

I am a newbie to Javascript. I have an extender control that is supposed to work with a FileUpload and an Image control. What I want to happen is when a file is selected for upload, at the firing of the OnChange event, what my code is meant to do is show the image that is selected for upload. Problem is nothing seems to be happening. Below is the jScript I have, I followed your example above to create a server class for the wiring of behaviors. Problem is I do not know what else to tweak to get this working. Can you please help?

/// <reference name="MicrosoftAjax.js"/>

Type.registerNamespace("Ajax.UserControls");

Ajax.UserControls.ImagePreview = function(element) {

//initialize the base

Ajax.UserControls.ImagePreview.initializeBase(this, [element]);

// Initialize instance level fields

this._defaultimage = null;

this._previewimage = null;

this._targetimageid = null;

}

Ajax.UserControls.ImagePreview.prototype =

{

   //call initialize on this first

   initialize: function() {

       Ajax.UserControls.ImagePreview.callBaseMethod(this, 'initialize');

       // Get a reference to the associated element

       var fileuploadcontrol = this.get_element();

       // Wire up handler for onmouseover

       var delegate = Function.createDelegate(this, this._onChange);

       $addHandler(fileuploadcontrol, 'change', delegate);

       this._onChange();

   }, //end initialize

   dispose: function() {

       //Add custom dispose actions here

       Ajax.UserControls.ImagePreview.callBaseMethod(this, 'dispose');

   }, //end dispose

   //Properties

   get_DefaultImage: function() {

       return this._defaultimage;

   },

   set_DefaultImage: function(value) {

       this._defaultimage = value;

   },

   get_PreviewImage: function() {

       return this._previewimage();

   },

   set_PreviewImage: function(value) {

       this._previewimage = value;

   },

   get_TargetImageID: function() {

       return this._targetimageid;

   },

   set_TargetImageID: function(value) {

       this._targetimageid = value;

   },

   // Event Handlers

   _onChange: function() {

       // Get a ref to the image element

       var  img = $get(this._targetimageid);

       //be sure there is an imagecontrol to work with

       if (img && !img.disabled && img.src != this.get_PreviewImage()) {

           // Set the source to the preview image

           img.src = this.get_PreviewImage();

       }

       else {

           if (img.src != this.get_DefaultImage) {

               //set it to the disabled image immediately

               img.src = this.get_DefaultImage();

           }

       }

   }

}

Ajax.UserControls.ImagePreview.registerClass('Ajax.UserCont rols.ImagePreview', Sys.UI.Behavior);

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

1. The curly braces are missing after the function keyword

AND/OR

2. The comma that separates the property accessors and the function proto-types is missing (Chris makes a mention of this explicity in the tutorial that the commas are not to be forgotten)

3. Also, test your app in FireFox. The Error Console will produce a URL to the .axd javascript source. If you click on the URL, the javascript is rendered in a Firefox window with the location of the error highlighted.

Putting the 2 together, here's what the code must look like:

set_DisabledText : function(value) {

this._disabledTextValue = value;

}, //**DO NOT FORGET THIS SEPERATOR- COMMA **

_onkeyup: function() //**DO NOT FORGET THESE BRACES **

{... rest of the code ..} //** NO COMMA IF THIS IS THE LAST PROTOTYPE OR ACCESSOR