导出到excel无效，仅添加了列

Question

因此，在它具有worbook.saveAs（）之前，它无法工作。但是我需要它来打开一个现有文件，然后保存它。不用写了。

我尝试使用此处不同问题中显示的方法，但是所有这些方法都在替换当前文件并创建一个新文件。

            SqlConnection cnn;
            string connectionString = null;
            string sql = null;
            string data = null;
            int i = 0;
            int j = 0;
            string filename = @"D:\ExcelFiles\DatabaseComp.xls";

            Microsoft.Office.Interop.Excel.Application xlApp;
            Microsoft.Office.Interop.Excel.Workbook xlWorkBook;
            Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
            object misValue = System.Reflection.Missing.Value;

            xlApp = new Microsoft.Office.Interop.Excel.Application();
            xlWorkBook = xlApp.Workbooks.Open(filename, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue, misValue);
            xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);

            connectionString = @"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Diether\Desktop\OJT KIOSK\DB_Kiosk.mdf;Integrated Security=True;User Instance=True";
            cnn = new SqlConnection(connectionString);
            cnn.Open();
            sql = "SELECT * FROM TBL_Company";
            SqlDataAdapter dscmd = new SqlDataAdapter(sql, cnn);
            DataSet ds = new DataSet();
            dscmd.Fill(ds);

            foreach (dynamic worksheet in xlWorkBook.Worksheets)
            {
                xlWorkSheet.Cells.ClearContents();
            }

            foreach (System.Data.DataTable dt in ds.Tables)
            {
                for (int i1 = 0; i1 < dt.Columns.Count; i1++)
                {
                    xlWorkSheet.Cells[1, i1 + 1] = dt.Columns[i1].ColumnName;
                }
            }

            for (i = 0; i <= ds.Tables[0].Rows.Count - 1; i++)
            {
                int s = i + 1;
                for (j = 0; j <= ds.Tables[0].Columns.Count - 1; j++)
                {
                    data = ds.Tables[0].Rows[i].ItemArray[j].ToString();
                    xlWorkSheet.Cells[s + 1, j + 1] = data;
                }
            }
            xlApp.DisplayAlerts = false;
            xlWorkBook.Save();
            xlWorkBook.Close(true, misValue, misValue);
            xlApp.Quit();
            xlApp.DisplayAlerts = false;

            releaseObject(xlWorkSheet);
            releaseObject(xlWorkBook);
            releaseObject(xlApp);