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# Bad Performance with Recursive Treeview Functions

Posted on 2004-09-17
Medium Priority
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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
Question by:fs25053
• 2

LVL 5

Accepted Solution

tzxie2000 earned 1000 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

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

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

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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