Missing reference for Run.Export in Telerik to export RadGridView data in Excel

I want to export RadGridview data in excel for this purpose I wrote the following code.

it is showing me an error. screenshoot is attached.

https://imgur.com/kmVLuyM

        private void tbExcel_Click(object sender, EventArgs e)
        {
            /*var excelML = new ExportToExcelML();
            excelML.RunExport(dGVClass,"C:\\Reports\\sample.xls",ExportToExcelML.ExcelMaxRows._65536, false);*/
            
            string exportFile = @"C:\\Reports\\Data.xlsx";
            using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
            {
                Telerik.WinControls.Export.GridViewSpreadExport exporter = new Telerik.WinControls.Export.GridViewSpreadExport(this.dGVClass);
                Telerik.WinControls.Export.SpreadExportRenderer renderer = new Telerik.WinControls.Export.SpreadExportRenderer();
                exporter.RunExport(ms, renderer);
                using (System.IO.FileStream fileStream = new System.IO.FileStream(exportFile, FileMode.Create, FileAccess.Write))
                {
                    ms.WriteTo(fileStream);
                }
            }
            
            /*GridViewSpreadExport spreadExporter = new GridViewSpreadExport(this.dGVClass);
            SpreadExportRenderer exportRenderer = new SpreadExportRenderer();
            spreadExporter.RunExport(@"C:\\exportedFile.xlsx", exportRenderer);*/
        }

how to get solution?