ASPxCallbackPanel Class

A callback panel control that allows you to update its content on a callback.

Assembly: DevExpress.Web.v19.1.dll

Declaration

C#
VB.NET

public class ASPxCallbackPanel :
    ASPxCollapsiblePanel

Public Class ASPxCallbackPanel
    Inherits ASPxCollapsiblePanel

Remarks

The Callback Panel is a container area that allows you to update its content using an AJAX-based callback technology.

Create a Callback Panel

Design Time

The ASPxCallbackPanel control is available on the DX.19.1: Navigation & Layout toolbox tab in the Microsoft Visual Studio IDE.

Drag the control onto a form and customize control settings, or paste the control markup in the page’s source code.

ASPX

<dx:ASPxCallbackPanel ID="ASPxCallbackPanel1" runat="server" Width="200px">
    <PanelCollection>
        <dx:PanelContent runat="server">
            <dx:ASPxTextBox ID="ASPxTextBox1" runat="server" Width="170px">
            </dx:ASPxTextBox>
        </dx:PanelContent>
    </PanelCollection>
</dx:ASPxCallbackPanel>

protected void Page_Load(object sender, EventArgs e)
{
    ASPxCallbackPanel cpanel = new ASPxCallbackPanel();
    cpanel.ID = "ASPxCallbackPanel1";
    cpanel.Controls.Add(new ASPxTextBox() { ID = "ASPxTextBox1", Text = "Test" });
    form1.Controls.Add(cpanel);
}

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    Dim cpanel As ASPxCallbackPanel = New ASPxCallbackPanel()
    cpanel.ID = "ASPxCallbackPanel1"
    cpanel.Controls.Add(New ASPxTextBox() With {
        .ID = "ASPxTextBox1",
        .Text = "Test"
    })
    form1.Controls.Add(cpanel)
End Sub

Client-Side API

The ASPxCallbackPanel’s client-side API is implemented with JavaScript language and exposed by the ASPxClientCallbackPanel object.

Availability	Available by default.
Class name	ASPxClientCallbackPanel
Access name	ClientInstanceName
Events	ASPxCallbackPanel.ClientSideEvents

Overview

The following API allows you to manipulate the callback panel on the client side:

The (ASPxClientCallbackPanel.PerformCallback) method - Sends a callback to the server.
The CallbackClientSideEventsBase.BeginCallback event - Allows you to perform custom actions when a callback is sent to the server side.
The ASPxCallbackPanel.Callback event - Allows you to handle a callback on the server side.
The CallbackClientSideEventsBase.EndCallback event - Allows you to perform custom actions when a callback comes from the server side.

Use the ASPxPanelContainerBase.Controls property to access the collection of the ASPxCallbackPanel‘s child controls.

Example

Full example - How to implement a custom loading panel for the ASPxCallbackPanel control

ASPX

<div class="sendCommentBlock">
    <dx:ASPxButton ID="Button" runat="server" Text="Post Comment" AutoPostBack="false">
        <ClientSideEvents Click="SendCommentCallback" />
    </dx:ASPxButton> 
    <br />
    <br />
    <dx:ASPxTextBox ID="TextBox" runat="server" Width="170px"></dx:ASPxTextBox>
</div>

<dx:ASPxCallbackPanel ID="CallbackPanel" ClientInstanceName="CallbackPanel" runat="server" CssClass="pnl" 
OnCallback="CallbackPanel_Callback" OnInit="CallbackPanel_Init">
    <ClientSideEvents BeginCallback="OnBeginCallback" EndCallback="OnEndCallback" />
    <PanelCollection>
        <dx:PanelContent>
            <dx:ASPxLabel ID="CountLabel" runat="server" Text="Comments Count : "></dx:ASPxLabel>
            <br />
            <br />
            <dx:ASPxLabel ID="NoCommentsLabel" runat="server" Text="No Comments" ForeColor="Gray">
            </dx:ASPxLabel>
        </dx:PanelContent>
    </PanelCollection>
</dx:ASPxCallbackPanel>
<dx:ASPxLoadingPanel ID="LoadingPanel" ClientInstanceName="LoadingPanel" runat="server" Modal="true" 
    HorizontalAlign="Center" VerticalAlign="Middle">
    <Image Url="Images/load.gif" Height="50px" Width="50px"></Image>
</dx:ASPxLoadingPanel>