Unable to get property 'value' in Telerik.Web.UI.RadInputExtender.prototype.isEmpty

2 posts, 0 answers
  1. Özcan
    Özcan avatar
    1 posts
    Member since:
    Feb 2016

    Posted 25 May Link to this post


    I received the following error , it triggered trough Telerik.Web.UI.WebResource.axd during processing submit event, so I cannot know which component causes the problem.


    In  Telerik.Web.UI.WebResource.axd  at line 31126 

     "if(!(a.value&&a.value.replace(/ /g,""))){return true;"

    it gives errors saying: 

    "Unable to get property 'value' of undefined or null reference"

    well the "a" is null ,  but which telerik or ui item it really refers? 


    The Call Stack is:

    Telerik.Web.UI.RadInputExtender.prototype.isEmpty [Line: 31126, Col: 1], Telerik.Web.UI.WebResource.axd

    Telerik.Web.UI.RadInputExtender.prototype.get_value [Line: 31132, Col: 7], Telerik.Web.UI.WebResource.axd
    Telerik.Web.UI.RadInputExtender.prototype._beforeSubmit [Line: 31248, Col: 1], Telerik.Web.UI.WebResource.axd
    Telerik.Web.UI.RadInputManager.prototype._beforeSubmit [Line: 31311, Col: 6], Telerik.Web.UI.WebResource.axd
    Telerik.Web.UI.RadInputManager.prototype._onSubmit [Line: 31307, Col: 58], Telerik.Web.UI.WebResource.axd
    Telerik.Web.UI.RadInputManager.WebForm_OnSubmit [Line: 31322, Col: 56], Telerik.Web.UI.WebResource.axd
    onsubmit [Line: 21, Col: 90], ManualInvoiceEdit2.aspx
    Sys.WebForms.PageRequestManager.prototype._onFormSubmit [Line: 15, Col: 22512], Telerik.Web.UI.WebResource.axd
    Sys.WebForms.PageRequestManager.prototype._doPostBack [Line: 15, Col: 15349], Telerik.Web.UI.WebResource.axd
    Sys.WebForms.PageRequestManager.prototype._doPostBackWithOptions [Line: 15, Col: 16021], Telerik.Web.UI.WebResource.axd
    Anonymous function [Line: 6, Col: 298], Telerik.Web.UI.WebResource.axd
    Global code [Line: 1, Col: 1], script block (423)


    I have 

    Telerik.Web.UI.dll 2016.2.504.40
    Telerik.Web.UI.Skins.dll 2016.2.504.40
    jQuery 1.11.1


    Any help or comment?








  2. Vessy
    Vessy avatar
    1357 posts

    Posted 27 May Link to this post

    Hi Özcan,

    The row where the error is thrown is part of the isEmpty() function of RadInputExtender. Are you using this method somewhere in the client-side logic of your page? Can you verify that the IDs of all input elements on the page are set properly (RadInputManager, RadTextBox, etc.)? You can add an override to the isEmpty function in a script tag on the problematic page and debug it as follows:
    Telerik.Web.UI.RadInputExtender.prototype.isEmpty =  function () {
        var input = $get(this._id);
        if (!(input.value && input.value.replace(/ /g, ''))) {
            return true;
        return (input.value === this._owner.get_emptyMessage() || input.value === this._owner.get_errorMessage());

    Unfortunately, even knowing the exact place where the error is thrown is not enough for us to determine the cause of the thrown error. I would advice that you start removing the controls from the page one by one in order to find the exact one which is causing the error. You can also find useful information on to isolate a problem from a real project in the following blog post:

    Do you need help with upgrading your ASP.NET AJAX, WPF or WinForms projects? Check the Telerik API Analyzer and share your thoughts.
  3. Telerik UI for ASP.NET Core is out
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