标题：[求助]判断某列是否为空的问题。

生产通知单增加一行，子表明细1和明细2增加八行，现在要多八行进行操作，如果支数列为空则删除，不为空则保存，一下代码错在哪里

Dim t1 As Table=Tables("生产通知单明细1")
Dim t2 As Table =Tables("生产通知单明细2")
For i As Integer = Tables("生产通知单明细1").Rows.count-8 To Tables("生产通知单明细1").Rows.count-1
 Dim dr1 As Row = t1.Rows(i)
 Dim dr2 As Row =t2.Rows(i)
If dr1("支数") IsNot Nothing Then
 dr1.save()
 dr2.save()
Else
 End If
 dr1.delete()
 dr2.delete()
Next

Dim t1 As Table=Tables("生产通知单明细1")
Dim t2 As Table =Tables("生产通知单明细2")
For i As Integer = Tables("生产通知单明细1").Rows.count-8 To Tables("生产通知单明细1").Rows.count-1
    Dim dr1 As Row = t1.Rows(i)
    Dim dr2 As Row =t2.Rows(i)
    If dr1.IsNull("支数") = False Then
        dr1.save()
        dr2.save()
    End If
    dr1.delete()
    dr2.delete()
Next

参考：

http://www.foxtable.com/help/topics/0595.htm

http://www.foxtable.com/help/topics/0426.htm