Inserting data into multiple worksheets on a single excel workbook

I am working on a method which exports data from two different C# lists into two excel worksheets in a single workbook using the following code

Microsoft.Office.Interop.Excel._Application app = new Microsoft.Office.Interop.Excel.Application();
                Microsoft.Office.Interop.Excel._Workbook workbook = app.Workbooks.Add(Type.Missing);



                Microsoft.Office.Interop.Excel._Worksheet worksheet1 = null;
                worksheet1 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.Sheets["Sheet1"];
                worksheet1 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.ActiveSheet;

                for (int i = 1; i < listExport.Count + 1; i++)
                {

                        worksheet1.Cells[i+1,1] = listExport[i - 1].time.ToString("HH:mm:ss");
                        worksheet1.Cells[i+1, 2] = listExport[i - 1].CC;
                        worksheet1.Cells[i+1, 3] = listExport[i - 1].term;                        

                }

                Microsoft.Office.Interop.Excel._Worksheet worksheet2 = null;
                worksheet2 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.Sheets["Sheet2"];
                worksheet2 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.ActiveSheet;

                for (int i = 1; i < AxiomSubSet.Count + 1; i++)
                {

                    worksheet2.Cells[i + 1, 1] = AxiomSubset[i - 1].time.ToString("HH:mm:ss");
                    worksheet2.Cells[i + 1, 2] = AxiomSubset[i - 1].CC;

                }

                string fileDestination = @"S:\Axiom Derivatives\Parser Project\axiom.xls";
                if (File.Exists(fileDestination))
                {
                    File.Delete(fileDestination);
                }

                workbook.SaveAs(fileDestination, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                workbook.Close(true, Type.Missing, Type.Missing);
                Process.Start(fileDestination);
                app.Quit();

But when I run the above method the first list is successfully processed but when assigning the second sheet at the following line it threw me error Invalid index. (Exception from HRESULT: 0x8002000B (DISP_E_BADINDEX))

worksheet2 ==Microsoft.Office.Interop.Excel._Worksheet)workbook.Sheets["Sheet2"];

Is it not the way to deal with multiple Excel sheets?

The second worksheet is probably not called Sheet2. It is best to just use the index instead.

Also, you need to call Activate to make Sheet 2 the active sheet:

before first sheet

worksheet1 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.Sheets[1];
workbook.Sheets[1].Activate(); 

before second sheet

worksheet2 = (Microsoft.Office.Interop.Excel._Worksheet)workbook.Sheets[2];
workbook.Sheets[2].Activate();