无法使用 C# 编写 excel

我正在编写一个非常简单的程序。它运行没有任何错误。但是没有任何东西写入 Excel 文件。我在某个地方错了吗？

  using Excel = Microsoft.Office.Interop.Excel;
  // I already add this reference into my project
  public Write()
  {
        Excel.Application xlApp;
        Excel.Workbook xlWorkBook;
        Excel.Worksheet xlWorkSheet;
        object misValue = System.Reflection.Missing.Value;
        xlApp = new Excel.Application();
        xlWorkBook = xlApp.Workbooks.Open(Directory.GetCurrentDirectory() + "''KKK.xlsx", 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "'t", false, false, 0, true, 1, 0);
        xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
        // This is all I want to write to my Excel file
        xlWorkSheet.Cells[1, 1] = "input";
        xlWorkBook.SaveAs(Directory.GetCurrentDirectory() + "''KQ" + ThoiGian(), Excel.XlFileFormat.xlWorkbookDefault, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
        xlWorkBook.Close(true, misValue, misValue);
        xlApp.Quit();
        releaseObject(xlApp);
        releaseObject(xlWorkBook);
        releaseObject(xlWorkSheet);
}

xlWorkSheet.Cells[1, 1].value = "input";