Refresh Data in a View After a Period of Time (ASP.NET Web Forms)

• Feb 02, 2024
• 3 minutes to read

This topic describes how to refresh data in a View after a period of time.

Create a WindowController

Add the following WindowController to the MySolution.Module.Web project:

File: MySolution.Module.Web\Controllers\AutoRefreshOnTimerMainWindowController.cs (AutoRefreshOnTimerMainWindowController.vb)

C#

using System;  
using DevExpress.ExpressApp;  
using DevExpress.ExpressApp.Web;  
using DevExpress.ExpressApp.Web.Templates;  

namespace AutoRefreshSample.Module.Web.Controllers {  
    public class AutoRefreshOnTimerMainWindowController : WindowController, IXafCallbackHandler {
        public AutoRefreshOnTimerMainWindowController() {  
            TargetWindowType = WindowType.Main;  
        }  
        protected override void OnActivated() {  
            base.OnActivated();  
            Frame.ViewChanged += Frame_ViewChanged;  
            ((WebWindow)Window).PagePreRender += CurrentRequestWindow_PagePreRender;  
        }  
        protected override void OnDeactivated() {  
            ((WebWindow)Window).PagePreRender -= CurrentRequestWindow_PagePreRender;  
            Frame.ViewChanged -= Frame_ViewChanged;  
            base.OnDeactivated();  
        }  
        void Frame_ViewChanged(object sender, ViewChangedEventArgs e) {  
            if (Frame.View != null) {  
                Frame.View.ControlsCreated += View_ControlsCreated;  
            }  
        }  
        void View_ControlsCreated(object sender, EventArgs e) {  
            RegisterXafCallackHandler();  
        }  
        private void RegisterXafCallackHandler() {  
            if (XafCallbackManager != null) {  
                XafCallbackManager.RegisterHandler("TimerCallback", this);  
            }  
        }  
        protected XafCallbackManager XafCallbackManager {  
            get {  
                return WebWindow.CurrentRequestPage != null ? ((ICallbackManagerHolder)WebWindow.CurrentRequestPage).CallbackManager : null;  
            }  
        }  
        void CurrentRequestWindow_PagePreRender(object sender, EventArgs e) {  
            WebWindow window = (WebWindow)sender;  
            string script = IsSuitableView() ? "window.startXafViewRefreshTimer(3000);" : "window.stopXafViewRefreshTimer();";  
            window.RegisterStartupScript(GetType().FullName, script);  
        }  
        // XAF calls this method every time an XAF callback is raised by the timer.
        public void ProcessAction(string parameter) {  
            if (IsSuitableView() && (Frame.View != null)) {  
                Frame.View.ObjectSpace.Refresh();  
            }  
        }  
        // Modify this method to enable the timer for required Views only.  
        protected virtual bool IsSuitableView() {  
            return Frame.View != null && Frame.View.IsRoot && !(Frame.View is DetailView) && !(Frame is NestedFrame) && !(Frame is PopupWindow);  
        }

    }  
}  

VB.NET

Imports System  
Imports DevExpress.ExpressApp  
Imports DevExpress.ExpressApp.Web  
Imports DevExpress.ExpressApp.Web.Templates  

Namespace AutoRefreshSample.Module.Web.Controllers
    Public Class AutoRefreshOnTimerMainWindowController  
        Inherits WindowController  
        Implements IXafCallbackHandler
        Public Sub New()  
            TargetWindowType = WindowType.Main  
        End Sub  
        Protected Overrides Sub OnActivated()  
            MyBase.OnActivated()  
            AddHandler Frame.ViewChanged, AddressOf Frame_ViewChanged  
            AddHandler (CType(Window, WebWindow)).PagePreRender, AddressOf CurrentRequestWindow_PagePreRender  
        End Sub  
        Protected Overrides Sub OnDeactivated()  
            RemoveHandler (CType(Window, WebWindow)).PagePreRender, AddressOf CurrentRequestWindow_PagePreRender  
            RemoveHandler Frame.ViewChanged, AddressOf Frame_ViewChanged  
            MyBase.OnDeactivated()  
        End Sub  
        Private Sub Frame_ViewChanged(ByVal sender As Object, ByVal e As ViewChangedEventArgs)  
            If (e.SourceFrame IsNot Nothing) AndAlso (e.SourceFrame.View IsNot Nothing) Then  
                AddHandler e.SourceFrame.View.ControlsCreated, AddressOf View_ControlsCreated  
            End If  
        End Sub  
        Private Sub View_ControlsCreated(ByVal sender As Object, ByVal e As EventArgs)  
            RegisterXafCallackHandler()  
        End Sub  
        Private Sub RegisterXafCallackHandler()  
            If XafCallbackManager IsNot Nothing Then  
                XafCallbackManager.RegisterHandler("TimerCallback", Me)  
            End If  
        End Sub  
        Protected ReadOnly Property XafCallbackManager() As XafCallbackManager  
            Get  
                Return If(WebWindow.CurrentRequestPage IsNot Nothing, (CType(WebWindow.CurrentRequestPage, ICallbackManagerHolder)).CallbackManager, Nothing)  
            End Get  
        End Property  
        Private Sub CurrentRequestWindow_PagePreRender(ByVal sender As Object, ByVal e As EventArgs)  
            Dim window As WebWindow = CType(sender, WebWindow)  
            Dim script As String = If(IsSuitableView(), "window.startXafViewRefreshTimer(3000);", "window.stopXafViewRefreshTimer();")  
            window.RegisterStartupScript(Me.GetType().FullName, script)  
        End Sub  
        ' XAF calls this method every time an XAF callback is raised by the timer.
        Public Sub ProcessAction(ByVal parameter As String)  
            If IsSuitableView() AndAlso (Frame.View IsNot Nothing) Then  
                Frame.View.ObjectSpace.Refresh()  
            End If  
        End Sub  
        ' Modify this method to enable the timer for required Views only.
        Protected Overridable Function IsSuitableView() As Boolean  
            Return Frame.View IsNot Nothing AndAlso Frame.View.IsRoot AndAlso Not(TypeOf Frame.View Is DetailView) AndAlso Not(TypeOf Frame Is NestedFrame) AndAlso Not(TypeOf Frame Is PopupWindow)  
        End Function
    End Class  
End Namespace  

Modify Default.aspx

Modify the Default.aspx file in the MySolution.Web project.

File: MySolution.Web\Controllers\Default.aspx

ASPX

<head runat="server">  
    <title>Main Page</title>  
    <meta http-equiv="Expires" content="0" />  
<script type="text/javascript">  
        window.xafViewRefreshTimer = null;  
        window.startXafViewRefreshTimer = function (delay) {  
            if (!window.xafViewRefreshTimer) {  
                window.xafViewRefreshTimer = window.setInterval(onXafViewRefreshTimer, delay);  
            }  
        }  
        window.stopXafViewRefreshTimer = function () {  
            if (window.xafViewRefreshTimer) {  
                window.clearInterval(window.xafViewRefreshTimer);  
                window.xafViewRefreshTimer = null;  
            }  
        }  
        window.isValidXafView = function () {  
            return !GetActivePopupControl(window.parent) || !GetActivePopupControl(window);  
        }  
        window.onXafViewRefreshTimer = function () {  
            if (isValidXafView()) {  
                RaiseXafCallback(globalCallbackControl, 'TimerCallback', '', '', false);  
            }  
        }  
    </script>  
 </head>