[RESOLVED] How do I combine similar items into one item a treeview?

[MikeFowler]

Right now I have the situation in which my treeview looks like:

Plan Heading
. Plan Item 1
. Plan Item 2
Plan Heading
. Plan Item 3
. Plan Item 4

and I would like to use code to combine the two Plan headings into one:

Plan Heading
.Plan Item 1
.Plan Item 2
.Plan Item 3
.Plan Item 4

What code is appropriate?
Thanks!
Mike Fowler

[jmcilhinney]

I haven't tested this code but it looks like it should work with the operations in this order.

Dim node1 As TreeNode 'The first instance.
        Dim node2 As TreeNode 'The duplicate instance.
 
        'Find the duplicate nodes and assign to the above variables here.
 
        Dim nodes As TreeNode() 'The nodes to be moved.
 
        'Remove the nodes from node2 and remove node2.
        node2.Nodes.CopyTo(nodes, 0)
        node2.Nodes.Clear()
        node2.Remove()
 
        'Add the nodes to node1.
        node1.Nodes.AddRange(nodes)

[MikeFowler]

The code you suggested did not completely solve my problem.
I added the following two Treeviews:
TreeView3.Nodes.Add("Plan")
TreeView3.Nodes(0).Nodes.Add("SDP")
TreeView3.Nodes(0).Nodes.Add("BIP")
TreeView4.Nodes.Add("Plan")
TreeView4.Nodes(0).Nodes.Add("SRS")
TreeView4.Nodes(0).Nodes.Add("BBB")
and the code:
Private Sub btnCombine_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCombine.Click
Dim myTreeNodeCollection As TreeNodeCollection = TreeView4.Nodes
Dim myTreeNodeArray(TreeView4.Nodes.Count - 1) As TreeNode
Dim tn As TreeNode = TreeView4.SelectedNode

TreeView4.Nodes.CopyTo(myTreeNodeArray, 0)
TreeView4.Nodes.Clear()
TreeView3.Nodes.AddRange(myTreeNodeArray)
TreeView3.Sorted = True
End Sub

And I get the following result in TreeView3:
Plan
.SDP
.BIP
Plan
.SRS
.BBB

and I need the result to be as combined:

Plan
.SDP
.BIP
.SRS
.BBB

Help!
Thanks!
Mike

[jmcilhinney]

You've left out the "Remove" line. First CopyTo, then Clear, then Remove, then AddRange.

[MikeFowler]

I left out the Remove line because the Clear statement also removes a treenode.
Having both Clear and Remove is redundant and the program will have a runtime error at the statement:
TreeView4.Nodes.Remove(tn)

An unhandled exception of type 'System.NullReferenceException' occurred in system.windows.forms.dll

Additional information: Object reference not set to an instance of an object.

this is my code:
Private Sub btnCombine_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCombine.Click
Dim myTreeNodeCollection As TreeNodeCollection = TreeView4.Nodes
Dim myTreeNodeArray(TreeView4.Nodes.Count - 1) As TreeNode
Dim tn As TreeNode = TreeView4.SelectedNode

TreeView4.Nodes.CopyTo(myTreeNodeArray, 0)
TreeView4.Nodes.Clear()
TreeView4.Nodes.Remove(tn)
TreeView3.Nodes.AddRange(myTreeNodeArray)
End Sub

[jmcilhinney]

You are removing all the nodes from TreeView4 and adding them to TreeView3. That is not what you want to do. You want to remove all the child nodes from the root node in TreeView4, then remove the root node from TreeView4, then add the child nodes to the root node of TreeView3.

[MikeFowler]

I need further instructions...would you please help me with using CopyTo,
Clear, Remove, and AddRange...
every thing I have tried has not worked.

Thanks!
Mike

[jmcilhinney]

I haven't tested this code but it looks like it should work with the operations in this order.

Dim node1 As TreeNode 'The first instance.
        Dim node2 As TreeNode 'The duplicate instance.
 
        'Find the duplicate nodes and assign to the above variables here.
 
        Dim nodes As TreeNode() 'The nodes to be moved.
 
        'Remove the nodes from node2 and remove node2.
        node2.Nodes.CopyTo(nodes, 0)
        node2.Nodes.Clear()
        node2.Remove()
 
        'Add the nodes to node1.
        node1.Nodes.AddRange(nodes)

Isn't that exactly what I've done here. In this example, node2 is the node that you want to be removed and have all its children moved to the other tree, and node1 is the node in the other tree that you want those children to be attached to. In your example, they are the nodes that read "Plan".

[MikeFowler]

I was successfull finally...
Thank you for your patience!

Here are my initializations:
TreeView3.Nodes.Add("Plan")
TreeView3.Nodes(0).Nodes.Add("SDP")
TreeView3.Nodes(0).Nodes.Add("BIP")
TreeView3.Nodes.Add("Plan")
TreeView3.Nodes(1).Nodes.Add("SRS")
TreeView3.Nodes(1).Nodes.Add("BBB")
Here is my code:

Dim node1 As TreeNode
Dim node2 As TreeNode
TreeView3.Nodes.Add("Plan")
node1 = TreeView3.Nodes(0)
node2 = TreeView3.Nodes(1)
Dim nodes(1) As TreeNode
node2.Nodes.CopyTo(nodes, 0)
node2.Nodes.Clear()
node2.Remove()
node1.Nodes.AddRange(nodes)
'remove the 2 heading if it has no children
Dim iHeadingChildren As Integer
iHeadingChildren = TreeView3.Nodes(1).Nodes.Count
If iHeadingChildren = 0 Then
TreeView3.Nodes(1).Nodes.Remove(TreeView3.Nodes(1))
End If

[jmcilhinney]

Glad it's working. Don't forget to mark your thread as Resolved from the Thread Tools menu.