如何從下一個數據表獲取Same Excel工作表的連續性從c＃導出到Excel

Question

當我將數據表導出到excel時，如何識別插入到Excel中的行數，並獲得同一Excel工作表的下一行位置以插入下一個數據表值？

var lines = new List<string>();

string[] columnNames = dataTable.Columns.Cast<DataColumn>().
                              Select(column => column.ColumnName).
                              ToArray();

var header = string.Join(",", columnNames);
lines.Add(header);

var valueLines = dataTable.AsEnumerable()
               .Select(row => string.Join(",", row.ItemArray));            
lines.AddRange(valueLines);

File.WriteAllLines("excel.csv",lines);

Answer 1

private static Microsoft.Office.Interop.Excel.Workbook mWorkBook;
private static Microsoft.Office.Interop.Excel.Sheets mWorkSheets;
private static Microsoft.Office.Interop.Excel.Worksheet mWSheet1;
private static Microsoft.Office.Interop.Excel.Application oXL;
public static void ReadExistingExcel()
{
   string path = @"C:\Tool\Reports1.xls";
   oXL = new Microsoft.Office.Interop.Excel.Application();
   oXL.Visible = true;
   oXL.DisplayAlerts = false;
   mWorkBook = oXL.Workbooks.Open(path, 0, false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "", true, false, 0, true, false, false);
   //Get all the sheets in the workbook
  mWorkSheets = mWorkBook.Worksheets;
   //Get the allready exists sheet
   mWSheet1 = (Microsoft.Office.Interop.Excel.Worksheet)mWorkSheets.get_Item("Sheet1");
   Microsoft.Office.Interop.Excel.Range range= mWSheet1.UsedRange;
   int colCount = range.Columns.Count;
   int rowCount= range.Rows.Count;
   for (int index = 1; index < 15; index++)
   {
      mWSheet1.Cells[rowCount + index, 1] = rowCount +index;
      mWSheet1.Cells[rowCount + index, 2] = "New Item"+index;
   }
   mWorkBook.SaveAs(path, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
   Missing.Value, Missing.Value, Missing.Value,    Missing.Value,Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,
   Missing.Value, Missing.Value, Missing.Value,
   Missing.Value, Missing.Value);
   mWorkBook.Close(Missing.Value, Missing.Value, Missing.Value);
   mWSheet1 = null;
   mWorkBook = null;
   oXL.Quit();
   GC.WaitForPendingFinalizers();
   GC.Collect();
   GC.WaitForPendingFinalizers();
   GC.Collect();
}