TreeView duplicating nodes and also blowing up IE

[Kristopher Wragg]

I'm having some serious problems with the TreeView control.

I've got a control that inherits TreeView and has some methods that
firstly create a TreeNode then does some recursive procedure to add all
the children from a database of a sort. Then once this is complete I
clear the nodes, then add the TreeNode so it should be the only root
node.

The only problem is that for some very VERY strange reason there are
two root nodes, with duplicate child nodes. This is very bizare as
this.Nodes.Count returns 1 and base.Nodes.Count also returns 1, so
there SHOULD be 1 root node but there are two.

Also, I created another TreeView inherited control that would act as
the base for this other TreeView which does all the painting by me, so
that I can have different colors for highlighting and some other things
and to make it double buffered and not flicker like mad but when I use
this control as the base instead of the .NET one when I do
this.Nodes.Add it basically blows the control up in Internet
Explorer...

So basically the TreeView is driving me slightly nuts, either I can
have a TreeView with duplicate nodes that flickers when it updates the
nodes, else I can have one thats flicker free and nice but only works
when I add the nodes in edit mode, if I try adding them in code it
kills Internet Explorer...

any ideas? I'm already invoking back on the UI thread if it's needed to
add the root node, so I know the problems not that...

 

[Kristopher Wragg]

Some code:

TreeNode rootNode = new TreeNode();
FormatNode(ref rootNode, service); // this passes a service class and
root and formats it text and color from the service classes details
rootNode = AddChildren(rootNode); // add its children with recursive
procedure...

base.Nodes.Clear();
if (this.InvokeRequired == true)
this.Invoke(new UpdateRootHandler(AddRoot),
rootNode);//this.Nodes.Add(rootNode);
else
this.Nodes.Add(rootNode);

-----------------------------------------------------------------------------------

private void AddRoot(TreeNode node)
{
this.Nodes.Add(node);
}

-----------------------------------------------------------------------------------

private TreeNode AddChildren(TreeNode node)
{
if (node == null)
{
Trace.WriteLine("AddChildren method has been passed a null
node");
return node;
}

Service parentService = (Service)node.Tag;
if (parentService == null)
{
Trace.WriteLine("AddChildren method has been passed a null
service instance");
return node;
}


// Retrieve list of child services
// & check the results returned are valid
ArrayList children = parentService.Children;
if (children == null || children.Count == 0)
{
Trace.WriteLine("Service: " + parentService.Name + " has no
children.");
return node;
}
// Increment each child service adding
// them one by one to the hierarchy
foreach (Service childService in children)
{
TreeNode childNode = null;

childNode = new TreeNode();
FormatNode(ref childNode, childService);
node.Nodes.Add(childNode);

// Recursively add a child's children
AddChildren(childNode);
}

return node;
}

 

[Kristopher Wragg]

These issue's are starting to drive me slightly mad, I can't understand
why either of these problems are occurring... according to the nodes
collection there IS only one root, I really can't understand why two
are being displayed, it really is rather strange... and why the other
is blowing up I really don't know... I've spent ages debugging with
traces and attaching to Internet Explorer's process...