ASPxClientTreeView.BeginCallback Event

Occurs when a callback for server-side processing is initiated.

Declaration

BeginCallback: ASPxClientEvent<ASPxClientBeginCallbackEventHandler<ASPxClientTreeView>>

Event Data

The BeginCallback event's data class is ASPxClientBeginCallbackEventArgs. The following properties provide information specific to this event:

Property	Description
command	Gets a command name that identifies which client action initiated a callback.

Remarks

The BeginCallback event, together with the ASPxClientTreeView.EndCallback event can be used to perform specific client-side actions, while a callback is being processed on the server side.

Example

The code below describes how you can handle the BeginCallback and EndCallback events, to display the explanatory text in a label while a callback is being processed on the server side.

ASPX

<dx:ASPxTreeView ID="ASPxTreeView1" runat="server" DataSourceID="XmlDataSource1" EnableCallBacks="True">
    <ClientSideEvents 
    BeginCallback="function(s, e) {label.SetText('Loading...');}" 
    EndCallback="function(s, e) {label.SetText('The data is loaded');}" />
</dx:ASPxTreeView>
<br />
<dx:ASPxLabel ID="ASPxLabel1" runat="server" Text="ASPxLabel" ClientInstanceName="label">
</dx:ASPxLabel>