删除行提示

当删除一行或多行时，如果要删除行中的“一级类别”、“二级类别”、“三级类别”、“四级类别”、“五级类别”、“六级类别”列的值与其它行不重复(类似不重复行)，则提示“该行包含类别 是否删除？”

请问如何设置？

http://www.foxtable.com/help/topics/0632.htm

\'删除行BeforeDeleteDataRow
Dim dr As DataRow = e.DataRow
Dim dr1 As List(of DataRow) = e.DataTable.Select("一级类别 Like \'" & dr("一级类别") & "\'And 二级类别 Like \'" & dr("二级类别") & "\'And 三级类别 Like \'" & dr("三级类别") & "\' And 四级类别 Like \'" & dr("四级类别") & "\' And 五级类别 Like \'" & dr("五级类别") & "\' And 六级类别 Like \'" & dr("六级类别") & "\'")
Dim d8 As String = dr("货品编号")
Dim d7 As String = " 货品编号:" & d8 & " 该行包含类别, 是否删除?"
If dr("货品编号") IsNot Nothing And dr1.count = 1 Then
If MessageBox.Show(d7,"提示",MessageBoxButtons.YesNo,MessageBoxIcon.Question) = DialogResult.No Then
        e.Cancel= True
Else
End If
End If

“一级类别”……“六级类别”列的值都非空时，能正常提示，如果某一列为空值时，不会提示，请问如何设置？

=和like对于null无效。

你应该逐列合成表达式：

Dim nms() As String = {"一级类别","二级类别","三级类别","四级类别","五级类别","六级类别"}
Dim flt As String
Dim dr As DataRow  = e.DataRow
For Each nm As String In nms
    If flt > "" Then
        flt = flt & " And "
    End If
   If dr.IsNull(nm) Then
        flt = flt & nm & " Is Null"
    Else
       flt = flt & nm & "= \'" & dr(nm) & "\'"
   End If
Next
If e.DataTable.Select(flt).Count = 1 Then

End If