Writing Data to Excel using C#

using Excel=Microsoft.Office.Interop.Excel;

using System.Reflection;

Excel.ApplicationClass excelApp = new Excel.ApplicationClass();

Excel.Workbook workbook = (Excel.Workbook)excelApp.Workbooks.Add(Missing.Value);

Excel.Worksheet worksheet;

// Opening excel file

workbook = excelApp.Workbooks.Open("D:\\test.xlsx", 0, false, 5, "", "", true, Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);

// Get first Worksheet

worksheet = (Excel.Worksheet)workbook.Sheets.get_Item(1);

// Setting cell values

((Excel.Range)worksheet.Cells["1", "A"]).Value2 = "5";

((Excel.Range)worksheet.Cells["2", "A"]).Value2 = "7";            

workbook.Save();

workbook.Close(0, 0, 0);  

excelApp.Quit();