[Solved] Cleared nodes get displayed again, node images are missing too

[Markus]

Hello everybody!

I'm using a RadTreeView control and implemented LoadonDemand. Whenever a node gets expanded, or the page gets loaded for the first time, I load the childelements of the node too, to estimate whether to display the expand item or not.

This code gets called when i load the page for the first time (or refresh it):

            ParameterTreeView.Nodes.Clear();
            ICollection<IHierarchyElement> rootColl = treeStructureService.ParameterRootElements();
            foreach (IHierarchyElement element in rootColl)
            {
                RadTreeNode node = CreateNode(element);
                ICollection<IHierarchyElement> childColl = treeStructureService.ParameterChildElements(node.Value);
                foreach (IHierarchyElement childElement in childColl)
                {
                    RadTreeNode cNode = CreateNode(childElement);
                    node.Nodes.Add(cNode);
                }
                ParameterTreeView.Nodes.Add(node);
            }

Creating a node happens like that:

private static RadTreeNode CreateNode(IHierarchyElement element)
        {
            RadTreeNode node = new RadTreeNode(element.Denotation);
            node.Value = element.Id;
            node.ExpandMode = TreeNodeExpandMode.ServerSideCallBack;
            node.ImageUrl = "~/RadControls/Treeview/Skins/ExampleSkins/ContextMenu/Folder.gif";
            node.ExpandedImageUrl = "~/RadControls/Treeview/Skins/ExampleSkins/ContextMenu/FolderOpen.gif";
            return node;
        }

and expanding a node like that:

foreach (RadTreeNode node in _root.Nodes)
            {
                //RadTreeNode node = CreateNode(element);
                ICollection<IHierarchyElement> childColl = treeStructureService.ParameterChildElements(node.Value);

                foreach (IHierarchyElement child in childColl)
                {
                    RadTreeNode childNode = CreateNode(child);
                    node.Nodes.Add(childNode);
                }
            }

My Problems in short:

Whenever i refresh the page and expand the root items again, already deleted items are shown.
The node items are only shown in layer 1 and 2. Everything beneath these layers has no items.
After refreshing, the duplicate items are missing the images too.

[Markus]

Whenever I refresh the page, the TreeViewNodesCollection is empty without deleting them beforehand. Allthough the old nodes are shown

[Dimitar Milushev]

Hi Markus,

Can you please open a support ticket and send us a sample project that demonstrates the issue you are having? This will make it much easier for us to understand the logic of your project, debug the problem and suggest you a solution.

Thank you for your understanding.

Regards,
Dimitar Milushev
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[Timothy Robbins]

I gather this person's issue with the nodes duplication was likely not setting the current node to expanded and setting the expandmode to client during the callback.

But what about the images?

during creation of a node, i set the imageurl to a given path.
however. after doing a postback, which hides and shows the tree's parent panel, all images in the imageurl are lost. This occurs in both firefox and ie.


RadTreeNode tn = new RadTreeNode(i.Name);
tn.Value = "I-" + i.Id.ToString();
tn.ImageUrl = "~/Images/Box.png";
e.Node.Nodes.Add(tn);

[Markus]

[quote]
I gather this person's issue with the nodes duplication was likely not setting the current node to expanded and setting the expandmode to client during the callback.
[/quote]

Could you please explain how nodes duplication and ExpandMode Settings play together in this case? And further how I can avoid this duplication issue.

Btw I found out that the nodes duplication issue doesn't happen with IE6

[Timothy Robbins]

Sure. Best to look at their demo.

From the c# source:

foreach (DataRow row in data.Rows)

{

//<snip> new child node creation here

}

e.Node.Expanded = true;

e.Node.ExpandMode = TreeNodeExpandMode.ClientSide;

I had the same issue if i used the tool in the manner I felt was obvious. My mistake though, its not immediately obvious why you have to do it this way, but if you think about it, you'll get it.