Initial load with AJAX

[Morten Andreasen]

Hi

I have some reports that i display in RadGrid that takes a while to generate. Therefore i would like to display the page with some "Loading" Html untill the data is ready.

It is unclear to me, from your documentation whether this is supported by default in RadGrid, or if i should wrap the grid control in a RadAjaxLoadingPanel.

Btv. the examples on EnableAJAXLoadingTemplate are outdated API wise.


Kind regards

[Sebastian]

Hi Morten,

You may consider ajaxifying the grid using RadAjaxManager or RadAjaxPanel and display RadAjaxLoadingPanel on initial load as illustrates in this help topic.

Best regards,
Sebastian
the Telerik team

[Morten Andreasen]

Hi Sebastian

Im trying hard to follow your example, but i get the following error message:

Message: Sys.InvalidOperationException: Could not find UpdatePanel with ID 'ctl00_webPartManager_g_a4c1cd77_25e2_4eec_8bab_4f41a4cd701b_ctl00_Panel2'. If it is being updated dynamically then it must be inside another UpdatePanel.

It puzzles me that you are using asp:Panel in your example and not asp:UpdatePanel

This is my source code

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server" OnAjaxRequest="RadAjaxManager1_AjaxRequest">
    <AjaxSettings>
        <telerik:AjaxSetting AjaxControlID="RadAjaxManager1">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="Panel1" LoadingPanelID="RadAjaxLoadingPanel1" />
                <telerik:AjaxUpdatedControl ControlID="residentGrid" />
            </UpdatedControls>
        </telerik:AjaxSetting>
    </AjaxSettings>
</telerik:RadAjaxManager>
<telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
    <script type="text/javascript">
        function pageLoad(sender, eventArgs) {
            if (!eventArgs.get_isPartialLoad()) {
                $find("<%= RadAjaxManager1.ClientID %>").ajaxRequest("InitialPageLoad");
            }
        }
    </script>
</telerik:RadCodeBlock>
<telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server" Height="75px"
    Width="75px" Transparency="50">
    <h1>
        Loading</h1>
</telerik:RadAjaxLoadingPanel>
<asp:Panel ID="Panel1" runat="server">
    <asp:Panel ID="Panel2" Visible="false" runat="server">
        <telerik:RadGrid ID="residentGrid" EnableAJAX="True" EnableAJAXLoadingTemplate="True"
            runat="server" AllowPaging="True" AllowSorting="True" PageSize="20" AutoGenerateColumns="False"
            GridLines="None" OnNeedDataSource="residentGrid_NeedDataSource">
            <MasterTableView>
                <Columns>
                    <telerik:GridBoundColumn HeaderText="AColumn" UniqueName="AColumn" DataField="AColumn" />
                </Columns>
            </MasterTableView>
        </telerik:RadGrid>
    </asp:Panel>
</asp:Panel>

protected void residentGrid_NeedDataSource(object source, Telerik.Web.UI.GridNeedDataSourceEventArgs e)
{
    residentGrid.DataSource = ParentWebPart.DataSource;
}
protected void RadAjaxManager1_AjaxRequest(object sender, Telerik.Web.UI.AjaxRequestEventArgs e)
{
    Thread.Sleep(2000);
    residentGrid.DataSource = ParentWebPart.DataSource;
    Panel2.Visible = true;
}

[Sebastian]

Hi Morten,

It seems that the error is produced due to nested MS UpdatePanels in your scenario. Verify that you wrapped the grid in asp Panels as illustrated in the documentation topic and remove any MS UpdatePanel containers. Note that RadAjaxManager injects UpdatePanels around the updated controls on-the-fly.

Best regards,
Sebastian
the Telerik team

[Morten Andreasen]

Im not using update panels - see code

[Sebastian]

Hello Morten,

From the id of the panel you provided I suppose that you use the grid in web part scenario with master/content pages - is this information correct? If so, double-check that you have not wrapped any content place holder (or other container) which hosts the grid in MS UpdatePanel, RadAjaxPanel or ajaxified it with RadAjaxManager.

If this does not help, I suggest you post the entire markup and code-behind of the page(s) which are related to the grid in this forum post. I will examine them in detail and will get back to you with my findings.

Regards,
Sebastian
the Telerik team