[C#]将数据写入已存在的excel文件

测试如下（xls/xlsx）：

　　     //将数据写入已存在Excel
        public static void writeExcel(string result, string filepath)
        {
            //1.创建Applicaton对象
            Microsoft.Office.Interop.Excel.Application xApp = new 

            Microsoft.Office.Interop.Excel.Application();

            //2.得到workbook对象，打开已有的文件
            Microsoft.Office.Interop.Excel.Workbook xBook = xApp.Workbooks.Open(filepath,
                                  Missing.Value, Missing.Value, Missing.Value, Missing.Value,
                                  Missing.Value, Missing.Value, Missing.Value, Missing.Value,
                                  Missing.Value, Missing.Value, Missing.Value, Missing.Value);

            //3.指定要操作的Sheet
            Microsoft.Office.Interop.Excel.Worksheet xSheet = (Microsoft.Office.Interop.Excel.Worksheet)xBook.Sheets[1];

            //在第一列的左边插入一列  1:第一列
            //xlShiftToRight:向右移动单元格   xlShiftDown:向下移动单元格
            //Range Columns = (Range)xSheet.Columns[1, System.Type.Missing];
            //Columns.Insert(XlInsertShiftDirection.xlShiftToRight, Type.Missing);

            //4.向相应对位置写入相应的数据
            xSheet.Cells[Column(列)][Row(行)] = result;

            //5.保存保存WorkBook
            xBook.Save();
            //6.从内存中关闭Excel对象

            xSheet = null;
            xBook.Close();
            xBook = null;
            //关闭EXCEL的提示框
            xApp.DisplayAlerts = false;          
            //Excel从内存中退出
            xApp.Quit();
            xApp = null;
        }