VB.net TreeView won't display on my form?

[WISara]

Hi all - I'm kind of a newbie. I've been researching this problem for a couple of days now and my searches haven't really come up with any solutions - hopefully I'm just doing something silly and someone will be able to point it out to me!

I'm working with a dataset - which is separated from the rest of the program by a datamanager class I made.

My form calls the datamanager class function that will call the function in the dataset to create a treeview based on the relational data in my dataset.

When the treeview is returned to the original sub that call it in the form I can see that all of the nodes are still intact - but nothing displays on the form?


Here's the code under the form load event:
Dim i As Integer
songTree.Nodes. Clear()
For i = 0 To My.Application. DataManager.get SongTree().Node s.Count - 1
songTree.Nodes. Add(My.Applicat ion.DataManager .getSongTree(). Nodes(i))
Next

songTree.Show()

Here's the code in my dataset:
Public Function gettreenode() As Windows.Forms.T reeView
Dim songTree As New Windows.Forms.T reeView
Dim nodeBand, nodeAlbum, nodeSong As New Windows.Forms.T reeNode
Dim rowBand, rowbandstoalbum s, rowAlbum, rowSong As DataRow

For Each rowBand In Me.Tables("Band s").Rows

nodeBand = New Windows.Forms.T reeNode
nodeBand.Text = rowBand("BandNa me")
nodeBand.Tag = rowBand
nodeBand = songTree.Nodes. Add(rowBand("Ba ndName"))
nodeBand.Tag = rowBand

songTree.Nodes. Add(nodeBand)

For Each rowbandstoalbum s In rowBand.GetChil dRows("BandAlbu msBand")
rowAlbum = rowbandstoalbum s.GetParentRow( "AlbumBandsAlbu ms")

nodeAlbum = nodeBand.Nodes. Add(rowAlbum("A lbumTitle"))
nodeAlbum.Tag = rowAlbum
nodeBand.Nodes. Add(nodeAlbum)

For Each rowSong In rowAlbum.GetChi ldRows("SongsAl bums")
nodeSong = nodeAlbum.Nodes .Add(rowSong("S ongTitle"))
nodeSong.Tag = rowSong
nodeAlbum.Nodes .Add(nodeSong)

Next
Next
Next

Return songTree
End Function

Any ideas?
Thanks!

[iburyak]

I didn't test it but do you have something like tree.refresh property?

Sometimes Microsoft tree nodes disappear but it is enough to move scrollbar up and down for them to show up again.

[WISara]

I've tried

tree.refresh
tree.visible = true


neither have any effect....

[iburyak]

Step through your code again it looks to me that function gettreenode loads tree directly and you don’t need to load it again in form load.

Use songTree.Show() before load it might help visualize on what is going on. You can remove this after it’ll start working as intended.

With a loop below you duplicate each node that already loaded by a function. Maybe it is better just to pass a tree as an object to your function and load it as you do but once.

For i = 0 To My.Application.DataManager.getSongTree().Nodes.Count - 1
   songTree.Nodes.Add(My.Application.DataManager.getSongTree().Nodes(i))
Next
 

Maybe I am wrong, it is hard to judge without testing.

Good Luck.