nodes duplicating with serverside drag n drop and load on demand

[Toby]

Hi,

I have a treeview loading dynamically from a web service which is all working fine. I have enabled server side drag n drop with a AjaxManager linked to the treeview.

It all works fine, but if you drag a node to a currently collapsed node, it will show the new node just dragged to it (as if it is expanded) but wont show the existing nodes until you manually click on it (where it loads from the webservice) Once it has done the load from the webservice it will then have a duplicate node of the one you have just added.

This issue sort of makes sences as in the drag n drop function it is adding the node from the serverside and then when the node is clicked it loads all the nodes from the database which will included the node that has just been moved - so will result in a duplicate.

private void PerformDragAndDrop(RadTreeViewDropPosition dropPosition, RadTreeNode sourceNode,
         RadTreeNode destNode)
        {
            if (sourceNode.Equals(destNode) || sourceNode.IsAncestorOf(destNode))
                return;

            sourceNode.Owner.Nodes.Remove(sourceNode);

            int iSourceNodeParentId = -1;
            int iSourceNodeId = Convert.ToInt32(sourceNode.Value);
            int iDestinationNodeId = Convert.ToInt32(destNode.Value);
            if (sourceNode.ParentNode != null)
                iSourceNodeParentId = Convert.ToInt32(sourceNode.ParentNode.Value);
            else
                iSourceNodeParentId = -1;

            int iGroupViewId = Convert.ToInt32(sourceNode.Attributes["GROUPVIEWID"]);

            WebSession webSess = (WebSession)Session["WebSession"];

            switch (dropPosition)
            {
                case RadTreeViewDropPosition.Over:
                    // child
                    if (!sourceNode.IsAncestorOf(destNode))
                    {
                        destNode.Nodes.Add(sourceNode);
                        // update db
                        webSess.MasterSystem.GroupsSystem.MoveNode(sourceNode.Value, destNode.Value);
                    }
                    break;

                case RadTreeViewDropPosition.Above:
                    // sibling - above
                    destNode.InsertBefore(sourceNode);
                    // update db
                    webSess.MasterSystem.GroupsSystem.MoveNodeOrder(iSourceNodeId, iSourceNodeParentId, iGroupViewId, ConfigurationConsts.NodeOrderDirection.nodUp);
                    break;

                case RadTreeViewDropPosition.Below:
                    // sibling - below
                    destNode.InsertAfter(sourceNode);
                    // update db
                    webSess.MasterSystem.GroupsSystem.MoveNodeOrder(iSourceNodeId, iSourceNodeParentId, iGroupViewId, ConfigurationConsts.NodeOrderDirection.nodDown);
                    break;
            }
        }

is there anyway rather than adding the node in this function - to just cause a reload from the webservice of the parent node where the node has just been dragged to - so instead of adding the node in manually - it can just load the information from the webservice.

Unless theres something else i should be doing?

thanks
Toby

[Veselin Vasilev]

Hi Toby Moxha,

The problem seems to be fixed in the latest version - Q2 2009. Please download it and test it.

Kind regards,
Veselin Vasilev
the Telerik team

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[Toby]

Hi,

Thanks for the reply, I am already using Q2 2009

thanks
Toby

[Toby]

is this not due to the fact that in the drag n drop code we are adding a node :

destNode.Nodes.Add(sourceNode);

and then the treeview reloads from the webservice which then results in a duplicate (as the new node is present in the dataset returned from the webservice).

[Veselin Vasilev]

Hi Toby Moxha,

Yes, I suppose that is the problem. What you can do is to clear the child nodes in OnClientNodePopulating event.

All the best,
Veselin Vasilev
the Telerik team

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[Toby]

thanks that seems a bit better but I can still get them to duplicate sometimes (its seems to be when dragging from a child to a parent, where the parent has just had a node added to it.

would it not be better to not add the node from server side at all (using destNode.Nodes.Add(sourceNode); )  and instead just use the webservice to populate the treeview (as the website will be up to date with the node data as it has been updated in the database.

Edit:

I have just tried not adding the nodes from the server side - which works fine. But I can still get the treeview nodes to sometimes duplicate when dragging items around - if you do a full refresh it is fine. is there a way to force all the nodes to rebind to the website (but keep the current heirachy open)

[Veselin Vasilev]

Hello Toby Moxha,

I am not sure why it behaves that way and I think it would be better if you open a support ticket and send us a sample project which demonstrates the problem.


Sincerely yours,
Veselin Vasilev
the Telerik team

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[Toby]

for anyone else with this issue the solution was :


A few quick tweaks fixed the first problem easily. In the PerformDragAndDrop server method you should add the dropped node to the destination node only if the destination node is expanded:



   if (destNode.Expanded || destNode.Nodes.Count == 0)
   {
            destNode.Nodes.Add(sourceNode);
   }