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Bad Performance with Recursive Treeview Functions

Posted on 2004-09-17
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Last Modified: 2008-01-09
Hi,

I’ve written some recursive treeview browsing functions. The sample below shows a function, which only searches and highlights a node.

But the performance is very, very bad. My Treeview has about 2000 nodes. Any suggestions?

Many thanks
Dominic Birrer

Here are the two subs (first the initial sub, then the recursive sub):

    '*** Loop sub through all rootnodes
  Public Sub SearchWAs(ByRef MyTrv As firstTreeView.Cls_firstTreeView, ByVal PK_WA As Integer)

        Dim RootNode As New firstTreeView.Cls_firstTreeNode()

        '*** Loop sub through all rootnodes
        For Each RootNode In MyTrv.Nodes

            '*** if node found
            If RootNode.PK = PK_WA And RootNode.Key1 = "WA" Then
                RootNode.Expand()
                RootNode.Key5 = "1"
                RootNode.BackColor = Color.Tomato
            End If

            '*** start the recursive sub
            SearchWAs_Rec(RootNode, PK_WA)
        Next

    End Sub

    '*** recursive Loop sub through all childnodes
    Public Sub SearchWAs_Rec(ByVal ParentNode As firstTreeView.Cls_firstTreeNode, ByVal PK_WA As Integer)

        Dim ChildNode As New firstTreeView.Cls_firstTreeNode()

        '*** recursive Loop sub through all childnodes
        For Each ChildNode In ParentNode.Nodes

            '*** if node found
            If ChildNode.PK = PK_WA And ChildNode.Key1 = "WA" Then
                ChildNode.BackColor = Color.Tomato
                ChildNode.Key5 = "1"
                '*** starts an other recursive sub to expand all nodes from the actual node up to the root node (this sub is build similar)
                ExpandParentNodes_Rec(ChildNode)
            End If

            '*** start itself with actual node as parentnode
            SearchWAs_Rec(ChildNode, PK_WA)

        Next

    End Sub
0
Comment
Question by:fs25053
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4 Comments
 
LVL 5

Accepted Solution

by:
tzxie2000 earned 250 total points
ID: 12083532
please test whether Enum is more quick:

Public Sub SearchWAs(Byval searchtreeview as treeview)
   IEnumerator myEnumerator = searchtreeview.nodes.GetEnumerator()
   while(myEnumerator.MoveNext())  
       dim curnode as treenode =(TreeNode)myEnumerator.Current
       if (curnode.Text.equal("WA")) then
                curnode.Expand()
                curnode.Key5 = "1"
                curnode.BackColor = Color.Tomato
       end if
   end while
 End Sub


0
 
LVL 6

Expert Comment

by:KGreg
ID: 12084585
This simplifies it.  I'm sure you can modify it to accomodate whatever treeview control you're using.  The first call you make should be to nodecollection(myTreeview.Nodes)


    Private Sub nodecollection(ByRef nodes As TreeNodeCollection)
        If Not nodes Is Nothing Then
            Dim n As TreeNode

            For Each n In nodes
                singlenode(n)
            Next

        End If
    End Sub

    Private Sub expandancestors(ByRef n As TreeNode)
        n.Expand()

        If Not n.Parent Is Nothing Then
            expandancestors(n)
        End If
    End Sub

    Private Sub singlenode(ByRef n As TreeNode)

        If n.Tag = "WA" Then
            n.Expand()
            n.BackColor = Color.Tomato
        End If

        If Not n.Parent Is Nothing Then
            ' This is a child node expand ancestors
            expandancestors(n.Parent)
        End If

        nodecollection(n.Nodes)
    End Sub

KGreg
0
 

Author Comment

by:fs25053
ID: 12084641
Many thanks ! This works very well!! Extremely increased performance...yeeeehaaaw..

Cheers,
Dominic

BTW - Here's the VB.Net Translation (if somebody else has the same problem):

    Public Sub SearchWAs(ByRef MyTrv As firstTreeView.Cls_firstTreeView, ByVal PK_WA As Integer)

        Dim myEnumerator As IEnumerator = MyTrv.Nodes.GetEnumerator

        ClearNodeSettings(MyTrv)

        While (myEnumerator.MoveNext())
            Dim RootNode As firstTreeView.Cls_firstTreeNode = CType(myEnumerator.Current, firstTreeView.Cls_firstTreeNode)

            If RootNode.PK = PK_WA And RootNode.Key1 = "WA" Then
                RootNode.Expand()
                RootNode.Key5 = "1"
                RootNode.BackColor = Color.Tomato
            End If

            SearchWAs_Rec(RootNode, PK_WA)

        End While

    End Sub

   Public Sub SearchWAs_Rec(ByVal ParentNode As firstTreeView.Cls_firstTreeNode, ByVal PK_WA As Integer)

        Dim myEnumerator As IEnumerator = ParentNode.Nodes.GetEnumerator

        While (myEnumerator.MoveNext())
            Dim ChildNode As firstTreeView.Cls_firstTreeNode = CType(myEnumerator.Current, firstTreeView.Cls_firstTreeNode)

            If ChildNode.PK = PK_WA And ChildNode.Key1 = "WA" Then
                ChildNode.BackColor = Color.Tomato
                ChildNode.Key5 = "1"

                ExpandParentNodes_Rec(ChildNode)

            End If

           SearchWAs_Rec(ChildNode, PK_WA)

        End While

    End Sub
0
 
LVL 6

Expert Comment

by:KGreg
ID: 12084731
I'd still recommend cleaning up the code by combining the enumerator with the code i've written.. it could speed it up more.

    Public Sub searchNodes(ByRef n As TreeNodeCollection, ByVal PK_WA As Integer)

        Dim myEnumerator As IEnumerator = n.GetEnumerator

        While (myEnumerator.MoveNext())
            singlenode(CType(myEnumerator.Current, firstTreeView.Cls_firstTreeNode))
        End While

    End Sub

    Public Sub singlenode(ByRef n As firstTreeView.Cls_firstTreeNode, ByVal PK_WA As Integer)
        If n.PK = PK_WA And n.Key1 = "WA" Then
            n.BackColor = Color.Tomato
            n.Key5 = "1"

            If Not IsNothing(n.Parent) Then ExpandParentNodes_Rec(n)
        End If

        searchNodes(n.Nodes)
    End Sub

KGreg
0

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