I was trying to copy all the data from 'Output.xls' file to the 'sheet1' of 'Dest.xls'. This is what my final code looks like-
string pathFileDestination = "C:\\Dest.xls";
Excel.Application excel = new Excel.Application();
Excel.Workbook wbDest = excel.Workbooks.Open(pathFileDestination, 0, false, 1, "", "", false, Excel.XlPlatform.xlWindows, 9, true, false, 0, true, false, false);
Excel.Worksheet WorksheetDest = wbDest.Sheets[1];
WorksheetDest.UsedRange.ClearContents();
WorksheetDest.get_Range("A1").Value = "No Data";
wbDest.Save();
wbDest.Close();
Excel.Workbook wbSource = excel.Workbooks.Open("C:\\Output.xls", 0, false, 1, "", "", false, Excel.XlPlatform.xlWindows, 9, true, false, 0, true, false, false);
Excel.Worksheet WorksheetSource = wbSource.Sheets[1];
WorksheetSource.UsedRange.Copy(Missing.Value);
Excel.Workbook wbDestination = excel.Workbooks.Open(pathFileDestination, 0, false, 1, "", "", false, Excel.XlPlatform.xlWindows, 9, true, false, 0, true, false, false);
Excel.Worksheet WorksheetDestination = wbDestination.Sheets[1];
WorksheetDestination.UsedRange.PasteSpecial(Excel.XlPasteType.xlPasteAll, Excel.XlPasteSpecialOperation.xlPasteSpecialOperationNone, misValue, misValue);
wbDestination.Save();
wbSource.Close();