TreeView - Remember all expanded nodes

[squatman]

Hi there,

I have found examples and discussions on how to remember the last selected node, and reselect/expand that node after a refresh.

What I want to do is remember all expanded nodes/node paths and after a refresh expand all previous paths.

How would I go about this..? Before the refresh would I have to recursively check the state of each node, store it and then after the refresh reassign the restored state..?

Any help or suggestion would be greatly appreciated.

Thank you.

[.paul.]

you could store all expanded nodes in a list, then after a refresh restore the expanded nodes:

Dim nodes As New List(Of TreeNode)

Private Sub TreeView1_AfterCollapse(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCollapse
    nodes.Remove(e.Node)
End Sub

Private Sub TreeView1_AfterExpand(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterExpand
    nodes.Add(e.Node)
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    nodes.Sort(Function(x, y) x.Level.CompareTo(y.Level))
    For Each n As TreeNode In nodes
        n.Expand()
    Next
End Sub

[squatman]

.paul.

Thanks for the response, sorry for taking so long to return to this.

I'm just looking at this again and can't seem to get it working.

How does it know which TreeView it is expanding/collapsing after refresh..?

Thank you.


Edit:

I have changed the code in the 'For' to:

TreeView1.Nodes(n.Name).Expand()

To refer to the TreeView, I have tried removing the 'AfterCollapse' handler during the fresh so it doesn't mess with the list. But I still can't get this to work...

Thanks again.


Edit 2:

I should probably note that some of the nodes will have the same 'name', this may be causing issues...

Thanks

[squatman]

Ok, figured this one out.

I had to Remove the handler for 'AfterExpand' whilst the 'For' was expanding the nodes.

Thank you very much .paul.

Another legend on these forums!


Just going to have a play at; if a parent node is collapsed and never again expanded, after the refresh it doesn't expand the parent because the child nodes were still expanded.

Any pointers would be appreciated.

Thanks again.