OnClientSelectedIndexChanging
The OnClientSelectedIndexChanging client-side event occurs when the selected item is being changed. This event is fired before the combobox selection has changed to a new item.
The event handler receives two parameters:
The instance of the combobox firing the event.
An eventArgs parameter containing the following methods:
get_item returns the item that is about to be selected.
set_cancel lets you prevent the selection from changing.
get_domEvent() returns the DOM event object.
This example prompts the user to confirm the selection change:
<script language="javascript" type="text/javascript">
function AllowSelectionChange(sender, eventArgs)
{
if (radprompt("Change "
+ sender.get_selectedItem().get_text() +
" to " +
eventArgs.get_item().get_text() + "?"))
eventArgs.set_cancel(false)
else
eventArgs.set_cancel(true);
}
</script>
<telerik:radcombobox
id="RadComboBox1"
runat="server"
onclientselectedindexchanging="AllowSelectionChange">
</telerik:radcombobox>
You can also use the OnClientSelectedIndexChanging event when you deploy dependant comboboxes on your page:
<script type="text/javascript">
function LoadCountries(combo, eventArgs) {
var countriesCombo = $find("<%= RadComboBox2.ClientID %>");
var item = eventArgs.get_item();
countriesCombo.set_text("Loading...");
if (item.get_index() > 0) {
countriesCombo.requestItems(item.get_value(), false);
}
else {
countriesCombo.set_text(" ");
countriesCombo.clearItems();
}
}
function ItemsLoaded(combo, eventArgs) {
var countriesCombo = $find("<%=RadComboBox2.ClientID%>");
if (combo.get_items().get_count() > 0) {
combo.set_text(combo.get_items().getItem(0).get_text());
combo.get_items().getItem(0).highlight();
}
combo.showDropDown();
}
</script>
<telerik:radcombobox id="RadComboBox1" runat="server" onclientselectedindexchanging="LoadCountries" />
<telerik:radcombobox id="RadComboBox2" runat="server" onclientitemsrequested="ItemsLoaded"
onitemsrequested="RadComboBox2_ItemsRequested" />
You can see a live example at Multiple Comboboxes