For Each dr As DataRow In DataTables("表A").DataRows
If dr.IsNull("A") = False
dr("B") = dr("A").split("/")(0)
If dr("A").split("/")(1).contains("-")
dr("C") = dr("A").split("/")(1).split("-")(0)
dr("D") = dr("A").split("/")(1).split("-")(1)
Else
dr("C") = Nothing
dr("D") = dr("A").split("/")(1).split("-")(0)
End If
Else
dr("B") = Nothing
dr("C") = Nothing
dr("D") = Nothing
End If
Next