Error On grid export to excel-ExcelML-URGENT

[Chandru]

Hi
I have 2 buttons in .aspx page ,one for pdf export and other for excel export.Pdf works okay.But on excel export, i get  error "RegisterRequiresControlState can only be called before and during PreRender. "
 I am using dynamically loaded user controls and the grid DataBind() is in the Page_Load of the user control.
The below is the Code in user control. What do I need to do to get rid of this error? I did see the forum answers where it says "Calling Rebind not after PreRender is not supported " .But I am not doing anything on PreRender knowingly.

protected void Page_Load(object sender, EventArgs e)
  {
      List<ReportDto> reportlt = BuildReport<ReportDto>();
      ReportGrid.DataSource = reportlt;
      ReportGrid.DataBind();
  }

Code in .ascx is

<telerik:RadGrid runat="server" SkinID="main" style="outline: none;" id="ReportGrid">
    <ExportSettings>
         <Pdf AllowAdd="false" AllowCopy="True" AllowModify="false" AllowPrinting="true" Author="RadTech"
              Keywords="None" PageBottomMargin=".1in" PageLeftMargin=".1in" PageRightMargin=".1in"
              PageTopMargin="1in" PaperSize="Letter" PageHeight="8.5in" PageWidth="11.69in" Title="Client QA -Case       Report" />
         <Excel Format="ExcelML" />
    </ExportSettings>

    <MasterTableView>
        <NoRecordsTemplate>
            There are no records to display
        </NoRecordsTemplate>
        <Columns>
       ....
....
...
            </Columns>
    </MasterTableView>
</telerik:RadGrid>

code in aspx.cs page is:

protected void BtnExportToExcel_Click(object sender,EventArgs e)

   {

       try

       {

           TrySearch();

       } 
        catch
        {
        }

           UserControl usr = new UserControl();

       usr = ReportHolder.FindControl("CaseReport") as UserControl;

       if (usr != null)

       {

           RadGrid grdExcel = usr.FindControl("ReportGrid") as RadGrid;

           grdExcel.ExportSettings.OpenInNewWindow = true;

           grdExcel.ExportSettings.ExportOnlyData = true;

           grdExcel.ExportSettings.IgnorePaging = true;

           grdExcel.MasterTableView.ExportToExcel();

       }

   }

[Daniel]

Hello Chand,

ExcelML export works with advanced data-binding only. Please examine the following links:
ExcelML basics
Advanced Data-binding (using NeedDataSource event)

Also when binding to List collection you have to set UseAllDataFields property to true.

Best regards,
Daniel
the Telerik team

[Jeff]

These links aren't working.  Have these documents moved?

[Vessy]

Hi Jeff,

The structure of our latest documentation is different than the one we had back in 2011, this is why the links above are invalid. You can access the linked resources via the following links:
https://docs.telerik.com/devtools/aspnet-ajax/controls/grid/functionality/exporting/export-formats/excelml-export/excelml-basics.html
and
https://docs.telerik.com/devtools/aspnet-ajax/controls/grid/data-binding/understanding-data-binding/server-side-binding/advanced-data-binding-(using-needdatasource-event)

Regards,
Vessy
Progress Telerik