Home/ Questions/Q 8220011
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-07T13:22:23+00:00

I’m using a user control, and added my report viewer and a custom toolbar.

  • 0

I’m using a user control, and added my report viewer and a custom toolbar. I want to create a custom navigation for it aswell, but for some reason when I want to check the total pages to decide whether or not to show the navigation buttons it either returns 0 or “This expression causes side effects and will not be evaluated” error..

I’ve ran out of ideas and not quite sure where to go from here..

<rsweb:reportviewer 
ID="rvReports" 
runat="server" ShowToolBar="False"
SizeToReportContent="True" AsyncRendering="false" />

codebehind:

rds = new Microsoft.Reporting.WebForms.ReportDataSource("dsName", myclasstoload());     
rvReports.LocalReport.DataSources.Add(rds);
rvReports.PageCountMode = PageCountMode.Actual;
rvReports.LocalReport.Refresh();
rvReports.DataBind();


if (rvReports.LocalReport.GetTotalPages() > 1)
{
 liFirst.Visible = true;
 liPrevious.Visible = true;
 liNext.Visible = true;
 liLast.Visible = true;
}

this is all on the databind event in my usercontrol (.ascx). Any help is more than appreciated.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    This msdn question is probably your answer, the GetTotalPages() method can’t be called until after the report has rendered. The relevant quote:

    The report server won’t calculate the total page count until rendering the first page of the report. The ReportViewer doesn’t request a page rendering from the server until the ASP.Net event PreRender. If you move the GetTotalPages call to a point after the ReportViewer.PreRender event has fired, you should get the behavior you want.

    See also the ASP.NET Page Lifecycle for reference.

    • 0