[RESOLVED] Populating a treeview [2003]

[JoakimG]

Hi

I would like to populate a treeview with texts from a collection (of objects Metal I've created). The objects contains several data, where some are texts.
I would like to be able to "sort" this collection in a treeview, where I want to have a couple of root-nodes and under them childnodes. I'll try to explain the structure with this picture:

 Metals - Metal manufacturer 01 - Steel 01
                                 - Steel 02
        - Metal Manufacturer 02 - Steel 03
                                 - Iron 01

This is supposed to be the treeview.
I could "hardcode" this structure, if I only knew the materials in the collection in advance. But I dont. So I have to iterate through the collection and add Manufacturers (and materials) as I go along.
I haven't been able to do this as of yet.

[18experience]

What have you done so far?

Dim parentnode as New TreeNode
Dim childnode as New TreeNode

parentnode.Text = "asdfasdf"

Me.TreeView1.Nodes.Add(parentnode)

childnode.Text = "childasdf"

parentnode.Nodes.Add(childnode)

That is how one would programatically add a node to a TreeView, and then add a child node to that node.

[stanav]

It's gonna be a pain in the neck trying to parse your text file the way it is right now... I suggest that you save the node's full path to the file instead. That is, instead of writing to the file like this

Metals - Metal manufacturer 01 - Steel 01
                                 - Steel 02
        - Metal Manufacturer 02 - Steel 03
                                 - Iron 01

You modify your code such that it'll write

Metals
Metals\Metal manufacturer 01
Metals\Metal manufacturer 01\Steel 01
Metals\Metal manufacturer 01\Steel 02
Metals
Metals\Metal manufacturer 02
Metals\Metal Manufacturer 02\Steel 03
Metals\Metal Manufacturer 02\Iron 01

And then as you read the text file, for each line you just create a new tree node base on its path.

[JoakimG]

hehe, well. . that wasnt a textfile. I was just trying to describe how I wanted the the treeview to look like

I have a collection of objects. The objects are of type Metal, a typ e I've made myself. In each object there is a string that holds the material-ID and a string that holds the manufacturer-ID. So I need to iterate through the collection, reading manufacturer from each object and compare that to the current childnodes of the root-node "Metals".
If I find a childnode that "equals" the string in metalObj.Manufacturer() I want to place a new childnode (materialnode) under the found childnode (\root\manufacturernode\new materialnode). But if I dont find any childnodes that has the same name (i.e manufacturer) I want to make a new childnode to the root (\root\new manufacturernode) and under that new childnode put the materialnode.

Hope this cleared thing a little bit. I think there are some ways to solve this that I already know of, but I really want to know if there are a simple smart and most of all efficient way of making this happen. Consider that I have to iterate alot and make many new node-arrays if im to use the simple add(node, childs()) method.

[JoakimG]

Hmm, i would really appreciate a little help with this subject. Im completely lost, because I get alot of errors. Such as if I store the manufacturers as strings in an array I only get the last metal dealt with.

Private Sub example()
     Dim length As new Integer
     Dim foundMetal As New Metal
     length = collMetal.count
     Dim stringArray(length) As String
     For i = 1 to length
          foundMetal = collMetal.Item(i)
          stringArray(i-1) = foundMetal.manufacturer()
     Next
End Sub

But the problem here is that all "foundMetal" gets cleared whenever the for-loop iterates one more step. This should not be a problem in my opinion, since I just want the string returned by foundMetal.Manufacturer().
I tried this with a listbox and the following code, which is the same as the one that doesnt work (the array above), and it works perfectly.

Private Sub example()
     Dim length As new Integer
     Dim foundMetal As New Metal
     length = collMetal.count
     Dim stringArray(length) As String
     For i = 1 to length
          foundMetal = collMetal.Item(i)
          lstbFound.Items.Add(foundMetal.Manufacturer)
     Next
End Sub

This is quite annoying, since this is a "small" problem of trying to find the solution to the real problem of building a treeview.

[18experience]

I am leaving out the declarations you have already shown.

Dim blnMatchFound as Boolean

for i = 0 to length - 1
blnMatchFound = False
foundMetal = colMetal.Item(i)
for each pnode as TreeNode in Me.TreeView1.Nodes
if pnode.Text = foundMetal.Manufacturer then
blnMatchFound = True
pnode.Nodes.Add(foundMetal.Material)
end if
next
if Not blnMatchFound then
Dim NewNode as New TreeNode
NewNode.Text = foundMetal.Manufacturer
Me.TreeView1.Nodes.Add(NewNode)
NewNode.Nodes.Add(foundMetal.Material)
end if
next

I haven't tested this, but the logic is there. For each metal, loop through the nodes in TreeView1 (your tree) looking a manufacturer. If you find one, just add the new node to the previously existing node and set your MatchFound variable to True. Then, after you have looped through all of your toplevel nodes, if MatchFound is False, add the Manufacturer and the new childnode of that manufacturer.

[JoakimG]

Thank you. Well, I did something resembling your algorithm and got it to work. The last problem was actually just that I had forgotten to add 2 lines of code that stored input from a form to the objects in question.

Well, I got this to work so im marking this as resolved. Thanks again