WebService based load on demand multi-column combobox

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  1. FA4488F9-481F-4FF0-8F36-9768A33C266D
    FA4488F9-481F-4FF0-8F36-9768A33C266D avatar
    7 posts
    Member since:
    Sep 2006

    Posted 20 Sep 2008 Link to this post


    RadControls version

    RadControls for ASPNET AJAX Q2 2008
    .NET version

    Visual Studio version

    programming language

    browser support

    all browsers supported by RadControls


    WebService based load on demand multi-column combobox.

    Telerik Note: You can achieve the same effect more easily with ASP.NET AJAX 4.0 client-side Templates and the RadComboBox client-side ItemDataBound event. For more information about the approach please see this blog post.

  2. 3C52E4D8-D34A-46C0-BC61-122FA63E083F
    3C52E4D8-D34A-46C0-BC61-122FA63E083F avatar
    42 posts
    Member since:
    Mar 2009

    Posted 23 Mar 2009 Link to this post

    The attached solution is throwing the following error
    Microsoft JScript runtime error: '0' is null or not an object
    when you type something in the textbox that does not exist in the dropdown. 
    This is occuring in Visual Studio 2008 during debugging.

    For Example, I start typing the first two or three characters of a matching record, then I type in a character that results in no matching record, and the error is thrown. I am using IE 7 on XP Pro, and the code that is throwing the error is:

    if (_this._xmlHttpRequest.readyState === 4 ) {  
                try {  
                    if (typeof(_this._xmlHttpRequest.status) === "undefined") {  
                catch(ex) {  
                _this._responseAvailable = true;  
                try {  
                finally {  
                    if (_this._xmlHttpRequest != null) {  
                        _this._xmlHttpRequest.onreadystatechange = Function.emptyMethod;  
                        _this._xmlHttpRequest = null;  

    this code does not exist in the attached JavaScript files, so I am assuming it is located in one of the axd file references located in the web.config. Any help on rectifying this solution would be helpful.

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