ASPxClientListBox.PerformCallback(parameter) Method

Sends a callback to the server, and generates the server-side ASPxListBox.Callback event, passing it the specified argument.

Declaration

PerformCallback(
    parameter: string
): void

Parameters

Name	Type	Description
parameter	string	A string value that represents any information that needs to be sent to the server-side ASPxListBox.Callback event.

Remarks

Use the PerformCallback method if you need to asynchronously go to the server and perform some server-side processing using AJAX-based callback technology. You can pass the required information to be collected on the client side as a string of arguments (for instance, in the “Name = Value;” form) via the PerformCallback method’s parameter parameter.

The PerformCallback method posts back to the server using the callback technology, and generates a server-side ASPxListBox.Callback event. The method’s parameter argument is passed to the ASPxListBox.Callback event’s handler as the CallbackEventArgsBase.Parameter property. So, the necessary server-side actions can be performed in the event’s handler based upon the values of the arguments, obtained by parsing the passed information string.

Note

The ASPxClientListBox.BeginCallback and ASPxClientListBox.EndCallback client events can also be used to perform necessary client actions before and after callback processing.

Example

This part of the Multiple Selection demo illustrates how to use multi-selection mode for the ASPxListBox editor.

ASPX

<dx:ASPxListBox ID="lbFeatures" runat="server" SelectionMode="CheckColumn" Height="210px"
    DataSourceID="Features" ValueField="ID" ValueType="System.String" TextField="Name">
    <ClientSideEvents SelectedIndexChanged="function(s, e) {lbModels.PerformCallback('1');}" />
</dx:ASPxListBox>
<dx:ASPxListBox ID="lbModels" runat="server" SelectionMode="CheckColumn" 
Height="210px" width="250px" ClientInstanceName="lbModels" 
DataSourceID="PhoneModels" ValueField="ID" ValueType="System.String" 
OnCallback="lbModels_Callback" >
   <Columns>
      <dx:ListBoxColumn FieldName="Name" Caption="Model" width="100%"/>
      <dx:ListBoxColumn FieldName="Price" width="50px"/>
   </Columns>
</dx:ASPxListBox>

C#

protected void lbModels_Callback(object sender, DevExpress.Web.CallbackEventArgsBase e) {
    FilterModels(lbFeatures.Items);
    lbModels.DataBind();
}
protected void FilterModels(ListEditItemCollection items) {
...     
}
...

VB.NET

Protected Sub lbModels_Callback(ByVal sender As Object, ByVal e As DevExpress.Web.CallbackEventArgsBase)
    FilterModels(lbFeatures.Items)
    lbModels.DataBind()
End Sub

Protected Sub FilterModels(ByVal items As ListEditItemCollection)
' ...
End Sub