for each dc1 As datacol in datatables("Zstb").datacols for each dc As datacol in datatables("Zszy").datacols if dc1.name = dc.name then Exit For elseif dc1.name <> dc.name then Dim Len As Integer = DataTables("Zszy").DataCols(dc.name).MaxLength DataTables("Zstb").DataCols.Add(dc.name, GetType(string),len) end if next next 上述代码是两个表中如果zstb表中无zszy表中的列就增加列,有就退出,无就增加,请问上述代码错哪儿了?