Aspx page: I bound the lstLocations dynamically. So it look like as below.
<telerik:RadListBox ID=”lstLocations” runat=”server” CheckBoxes=”true” Width=”520px”
Height=”130px”>
</telerik:RadListBox>
// Select All checkbox buttons
<asp:CheckBox CssClass=”CBFull” ID=”chkSelectAll” runat=”server” Text=”Select All”
onclick=”javascript:return ToggleAllLocations(this);” />
// Add below function in javascript function
function ToggleAllLocations(checkBox) { //ctl00_ContentPlaceHolder1_RadDockLocFilter_C_lstLocations is a client id of radlistbox var listbox = $find("ctl00_ContentPlaceHolder1_RadDockLocFilter_C_lstLocations"); var j = listbox.get_checkedItems().length; if (!document.getElementById(checkBox.id).checked) { for (var i = 0; i < j; i++) { listbox.get_checkedItems()[0].uncheck(); } } else { for (var i = 0; i < listbox.get_items().get_count(); i++) { var item = listbox.getItem(i); listbox.trackChanges(); item.set_checked(true); listbox.commitChanges(); } } return true; }