Here I will explain how you can use C# code to write things to Excel. Certainly, there are several good pre-made plugins available which directly write your output to an Excel file. This is more like learning the old school way of how it was done.
Create a simple Console Application to interop excel dll.

Now, you can paste this code in your class.
  1. class Program
  2. {
  3. static void Main(string[] args)
  4. {
  5. Application xlApp = new Application();
  7. if (xlApp == null)
  8. {
  9. //just to check if we get hold of the excel aplication
  10. return;
  11. }
  14. Workbook xlWorkBook;
  15. Worksheet xlWorkSheet;
  16. object misValue = System.Reflection.Missing.Value;
  18. xlWorkBook = xlApp.Workbooks.Add(misValue);
  19. xlWorkSheet = (Worksheet)xlWorkBook.Worksheets.get_Item(1);
  20. xlWorkSheet.Cells[1, 1] = "Sheet 1 content";
  21. //you can basically do what every you want
  23. xlWorkBook.SaveAs("f:\\csharp-Excel.xls", XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
  24. xlWorkBook.Close(true, misValue, misValue);
  25. xlApp.Quit();
  27. releaseObject(xlWorkSheet);
  28. releaseObject(xlWorkBook);
  29. releaseObject(xlApp);
  32. }
  34. //so that we dont leave any memory leaks
  35. private static void releaseObject(object obj)
  36. {
  37. try
  38. {
  39. System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
  40. obj = null;
  41. }
  42. catch (Exception ex)
  43. {
  44. obj = null;
  45. }
  46. finally
  47. {
  48. GC.Collect();
  49. }
  50. }
  51. }
This will create a file and write the sample text in it. The file won't even be visible. So, everything is done in the background.