Last Updated: 08 Jan 2020 12:20 by ADMIN
Release R1 2020
Created on: 08 Jan 2020 12:13
Category: MonthYearPicker
Type: Bug Report
MonthYearPicker throws a Sys.ArgumentUndefinedException error: Value cannot be undefined.

This bug started happening in version Telerik 2019.3.917, and is still present in Telerik 2019.3.1023.

The reproduction is extremely basic:

<table runat="server">
            <telerik:RadMonthYearPicker ID="MonthYear" runat="server" Width="150px">
            <asp:Button ID="btnGenerate" runat="server" Text="Get Report" OnClick="btnGenerate_Click" />

 protected void Page_Load(object sender, EventArgs e)
        if (!IsPostBack)
            MonthYear.SelectedDate = DateTime.Today;
            MonthYear.MaxDate = DateTime.Today.AddDays(1);

When i select a month/date from the control and submit the page i'm getting this script error:

The page freezes and i can get this error in Chrome from browser right-click->inspect->Console tab

Uncaught Sys.ArgumentUndefinedException: Sys.ArgumentUndefinedException: Value cannot be undefined.
Parameter name: handler
    at Function.Error$create [as create] (
    at Object.Sys._errorArgument (
    at Function.Error$argumentUndefined [as argumentUndefined] (
    at Function$_validateParameterType [as _validateParameterType] (
    at Function$_validateParameter [as _validateParameter] (
    at Function$_validateParams [as _validateParams] (
    at EventHandlerList$removeHandler [as removeHandler] (
    at Telerik.Web.UI.RadMonthYearPicker.remove_popupClosed (
    at Telerik.Web.UI.RadMonthYearPicker.dispose (
    at _Application$disposeElement [as disposeElement] (

You can see at the base of the call stack that the RadMonthYearPicker control is referenced. 

1 comment
Posted on: 08 Jan 2020 12:20

Hi Mark,

Thank you for reporting this error!

I have good news that the issue will be fixed in R1 2020, to be out on January 15.

Best Regards,
Progress Telerik

Get quickly onboarded and successful with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.