主题：递归生成目录树的效率问题

'---在各表名下生成目录树节点
e.Sender.StopRedraw
Dim pnd As WinForm.TreeNode = e.Node
If e.Node.level = 1 Then  '如果是表名节点
    e.Node.Nodes.Clear  '清空原有节点
    Dim tbName As String = e.Node.Name
    Dim dr As DataRow = DataTables("表B").Find("表名 = '" & tbName & "'")
    If dr IsNot Nothing Then
        Dim Cols As String = dr("目录树列")
        Dim Cols_sort As String = Cols.replace("|",",")
            
        Dim nds As new List(Of WinForm.TreeNode)
        For i As Integer = 0 To Cols.Split("|").Length
            nds.Add(e.Node)
        Next
        For Each arys As String() In DataTables(tbName).GetValues(Cols, "", Cols_sort)
            Dim flag As Boolean = False
            For i As Integer = 0 To arys.Length - 1
                If nds(i+1).Name <> arys(i) OrElse flag Then
                    flag = True
                    nds(i+1) = nds(i).Nodes.Add(arys(i))
                End If
            Next
        Next
       
        e.Node.Expand
    End If
End If
e.Sender.ResumeRedraw

此主题相关图片如下：360截图20141127-4.jpg

点击产品编码时会出错

'---在各表名下生成目录树节点
e.Sender.StopRedraw
Dim pnd As WinForm.TreeNode = e.Node
If e.Node.level = 1 Then  '如果是表名节点
    e.Node.Nodes.Clear  '清空原有节点
    Dim tbName As String = e.Node.Name
    Dim dr As DataRow = DataTables("表B").Find("表名 = '" & tbName & "'")
    If dr IsNot Nothing Then
        Dim Cols As String = dr("目录树列")
        Dim Cols_sort As String = Cols.replace("|",",")
       
        Dim nds As new List(Of WinForm.TreeNode)
        For i As Integer = 0 To Cols.Split("|").Length
            nds.Add(e.Node)
        Next
        If nds.Count > 2 Then
            For Each arys As String() In DataTables(tbName).GetValues(Cols, "", Cols_sort)
                Dim flag As Boolean = False
                For i As Integer = 0 To arys.Length - 1
                    If nds(i+1).Name <> arys(i) OrElse flag Then
                        flag = True
                        nds(i+1) = nds(i).Nodes.Add(arys(i))
                    End If
                Next
            Next
        Else
            For Each arys As String In DataTables(tbName).GetValues(Cols, "", Cols_sort)
                nds(1) = nds(0).Nodes.Add(arys)
            Next
        End If
       
        e.Node.Expand
    End If
End If
e.Sender.ResumeRedraw

对比了一下，如果能直接用Buildtree生成的话，那样的速度还是更快，但我这样的情况，也可以了。

 

谢谢了！

再请教一下甜老师，buildtree的原理是什么样的，按理也是取各列组合值来遍历生成目录树，为什么上面这个方式还是要比buildtree那样慢，尤其节点数量多时，谢谢！

 buildTree就是单纯的递归，没什么异样。

但是为什么现在用13楼那样的方式生成速度就是比buildtree直接生成慢，其他功能都完全可以了。

 测试了下，速度也不是很慢，跟buildtree应该是差不了多少的啊

 

e.Sender.ExpandAll