I have a few instances where I need OnClientSelectedIndexChanging inorder to stop the listbox selectedIndexChanged event from posting back in certain cases. In those cases I stop it from posting back by setting the e.set_cancel(true);

function CheckForListBoxReorder_OnClientEvent(sender, e) {
    if (ListboxReordered()) {
        alert('Please save changes to the bus order.');
        e.set_cancel(true);
    }
}

This works very nicely, but I'm getting many errors because although it looks like it's still selected to the proper row in the listbox the selectedIndex is now -1.

The control should provide support for the JAWS screen readers, which will enable it for use by visually impaired users.

More details are available in the following forum thread - https://www.telerik.com/forums/how-is-listbox-usable-for-screen-readers

A workaround is to disable the embedded jQuery and use an older version (for example, 1.11.1 which is the previous version the suite used): https://docs.telerik.com/devtools/aspnet-ajax/controls/scriptmanager/disabling-the-embedded-jquery

Repro steps:

1. put a listbox on the page
2. configure it so it does postbacks (e.g., on selection changed, or any other feature)
3. ivnoke said postback (e.g., select an item)

Expected: the action is carried off

Actual: Firefox throws TypeError: access to strict mode caller function is censored

Sample markup

        <telerik:RadListBox runat="server" ID="rlb1" OnSelectedIndexChanged="rlb1_SelectedIndexChanged" AutoPostBack="true">
            <Items>
                <telerik:RadListBoxItem Text="first" Selected="true" />
                <telerik:RadListBoxItem Text="second" />
            </Items>
        </telerik:RadListBox>

Please see ticket http://www.telerik.com/forums/color-individual-buttonlistitem-radcheckboxlist

The System.Web.UI.WebControls.ListItem class provides a Attributes property.
The Telerik.Web.UI.ButtonListItem class not.

I need to set the individual color of an item server side.

RadListBox allows to declaratively bind the Text and Value properties of the ListItems, e.g:

<telerik:RadListBox runat="server" DataTextField="Text" DataValueField="Id">

Unfortunately, this is not possible for the ImageUrl property.

My Suggestion: please allow to also bind the ImageUrl declaratively as known from other controls, e.g:

<telerik:RadListBox runat="server" DataTextField="Text" DataValueField="Id"
    DataImageUrlField="..."

// and maybe even like this:

    DataImageUrlFormatString="..." DataImageUrlFields="...">

Hi,

Would love to have feature for reorder animation and drop placeholder when user is reordering the item(s) in the Radlistbox.

A example would be the list in invisionapp.com as attached.

Another example would be like JQUERYUI's sortable plugin. 
URL: https://jqueryui.com/sortable/#placeholder.

Thanks.

The error is observed when an item that is added from the client-side is to be transferred to other RadListBox from a RadListBox that is loading on demand. Unfortunately the control supports such scenario only when that transfer is made from the server side.