OnClientItemsRequesting
The OnClientItemsRequesting client-side event occurs when EnableLoadOnDemand is True and the combobox is about to send a server-side request to load more items. This event fires before the items are added to the combobox' Items collection.
The event handler receives two parameters:
The instance of the combobox firing the event.
An eventArgs parameter containing the following methods:
get_text returns the text currently in the input area.
get_context returns a context object (implements IDictionary) that is passed to the server-side code that handles the request for items.
set_cancel lets you prevent the items request.
get_domEvent() returns the DOM event object.
This event can be used to pass context information to the server for it to use in servicing the load-on-demand request, or to cancel the load-on-demand request. The following example uses the OnClientItemsRequesting event to prevent the combobox from requesting more items unless the user types at least three characters:
<script language="javascript" type="text/javascript">
function OnClientItemsRequesting(sender, eventArgs) {
if (eventArgs.get_text().length < 3)
eventArgs.set_cancel(true)
else
eventArgs.set_cancel(false);
}
</script>
<telerik:RadComboBox
ID="RadComboBox1"
runat="server"
EnableLoadOnDemand="True"
OnItemsRequested="RadComboBox1_ItemsRequested"
OnClientItemsRequesting="OnClientItemsRequesting">
</telerik:RadComboBox>