[求助]怎么用代码删除和添加列非临时表

Dim pd As Date
pd=e.Form.Controls("DateTimePicker2").Value
Dim year As Integer = pd.Year
Dim month As Integer = pd.Month-1
Dim day As Integer = pd.Day
if Tables("报表明细").Cols.Contains("日期_31") then
  if day = 30 then
  DataTables("报表明细").DataCols.Delete("日期_31")
  end if
else
  if day = 31 then
  DataTables("报表明细").DataCols.Add("日期_31", GetType(Integer))
  end if
end if

我用临时表的删除方法没办法删除和添加

http://www.foxtable.net/help/topics/2122.htm

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