C#将数据集连接到Excel并显示

private void WriteExcel(string filename,string sql)  {      Application excel;      _Workbook xBk;      _Worksheet xSt;      _QueryTable xQt;      excel = new ApplicationClass();      if (excel == null)      {          MessageBox.Show("无法创建Excel对象，可能您的机子未安装Excel");          return;      }       xBk = excel.Workbooks.Add(true);      xSt = (_Worksheet)xBk.ActiveSheet;      string Conn = "ODBC;DRIVER=SQL Server;SERVER=" + host + ";UID=sa;PWD=58325245;DATABASE=CMSChina";      xQt = xSt.QueryTables.Add(Conn, xSt.get_Range(excel.Cells[1, 1], excel.Cells[1, 1]), sql);      xQt.Name = "导出示例";      xQt.FieldNames = true;      xQt.RowNumbers = false;      xQt.FillAdjacentFormulas = false;      xQt.PreserveFormatting = false;      xQt.BackgroundQuery = true;      xQt.RefreshStyle = XlCellInsertionMode.xlInsertDeleteCells;      xQt.AdjustColumnWidth = true;      xQt.RefreshPeriod = 0;      xQt.PreserveColumnInfo = true;      xQt.Refresh(xQt.BackgroundQuery);      excel.Visible = true;  }