我套用了软件的多选目录树代码，如何将他变成按年/月汇集

此主题相关图片如下：ttt1.jpg

代码如下：

Dim trv As WinForm.TreeView = e.Sender
Dim flt As String
For Each nd As WinForm.TreeNode In e.node.Nodes \'同步子节点选中状态
    nd.Checked = e.Node.Checked
Next
If e.node.ParentNode IsNot Nothing Then \'去掉父节点选中状态
    e.node.ParentNode.Checked = False
End If
For Each nd As WinForm.TreeNode In trv.AllNodes
    If nd.Level > 0 AndAlso nd.ParentNode.Checked Then \'如果父节点选中
        Continue For \'跳过此节点,处理下一结点
    End If
    If nd.Checked Then
        If flt > "" Then
            flt = flt & " Or "  \'注意用or而不是And
        End If
        If nd.Level = 0 Then \'注意下面的条件都要用括号括起来
            flt = flt & "( 报销日期 = \'" & nd.Text & "\')"
        Else
            flt = flt & "( 报销日期 = \'" & nd.ParentNode.Text & "\' And 费用类型 = \'" & nd.Text & "\')"
        End If
    End If   
Next
Tables("费用报销表").Filter = flt

谢谢!