主题：菜单按钮控件代码

老师，下面是菜单按钮控件代码，其意思是点击此按钮时，将HTB1指定的列复制到XMJDB1，HTB1中列“HTBH”是唯一的，原来的按钮是是没有限制复制次数的，现在要增加条件，就是如果已经复制行到XMJDB1，如果XMJDB1的“ND”“YF”为空时，则相同的行不能再从HTB1复制到XMJDB1，这样就避免当月因误点按钮重复在XJMJDB1生成数据行。代码如下，现在如何在黄色代码处加上条件代码呢？？请老师指导

If User.IsRole("经办人") Then
    For Each r As Row In Tables("HTB1").Rows
      If r("XZH") = True Then
       Dim dS As DataRow
         dS = DataTables("HTB").Find("HTBH = '" & e.DataRow("HTBH") & "'" ) ‘在XMJDB1里查找HTBH 
         If dS Is Nothing '如果找到, 则设置各列内容

            判断XMJDB1的“ND”“YF”列为空的代码 就是在XMJDB1里找到合同编号且没有“ND”“YF”  为空的行时，复制下列列到XMJDB1，否则提示“本月已经。。。。。”                                           

           Dim nma() As String = { "XMLB","XMBM","XMMC","HTBH","HTMC","KSJM","KSMC","FYDL","HTFYLB","HTJE","LJZFGCK","分项名称","YZFYFK","YFJK" } 'A表数据来源列
           Dim nmb() As String = { "XMLB","XMBM","XMMC","HTBH","HTMC","KSJM","KSMC","FYDL","FYLB","HTJE","LJYFJDK","分项名称","YFGCK","GCJK" } 'B表数据接收列
           Dim dr As DataRow = DataTables("XMJDB1").AddNew         
            For i As Integer = 0 To nma.Length - 1
              dr(nmb(i)) = r(nma(i))
          Next
      End If
    Next
End If