Assembly: Microsoft.ReportViewer.WinForms (in microsoft.reportviewer.winforms.dll)
Pagination in a processed report occurs when the report is rendered. Until the report is rendered, the total page count is unknown.
Rendering a report using the Estimate mode can help improve the performance of report rendering. You can change the PageCountMode property of ReportViewer to control the page count mode it uses when rendering a report in the report area. To specify the page count mode when you render a report programmatically, use Render. You can then use the GetTotalPages method to retrieve the total number of pages in the rendered report.
Rendering in Estimate mode can be more performant than Actual mode