Grid row reordering with self-referencing hierarchy

[Max McKinney]

I have a RadGrid that I'm using self-referencing hierarchy and row reordering.  I would like an example of how to trap whether a parent row is being dropped as a child of itself.

For tree view, I use something like:

if(sourceNode.Equals(destNode) || sourceNode.IsAncestorOf(destinationNode))
return;

[Max McKinney]

does anyone have any idea how to go about doing this?  we're still struggling with finding a solution.

[Max McKinney]

still looking for help please.

[Marin]

Hello Max,

 You can handle the RowDrop event on the server and there you have access to the destination item and the dragged items. Once you have retrieved them you can determine whether one is child of the other by examining their DataKeyNames or specific values of their columns. Here is a sample code based on the hierarchy in the live demo for self-referencing hierarchy:

protected void RadGrid1_RowDrop(object sender, GridDragDropEventArgs e)
        {
            var sourceItemID = e.DraggedItems[0]["EmployeeID"].Text;

            var destinationItem = e.DestDataItem.ChildItem.NestedTableViews[0];

            if (sourceItemID == destinationItem.ParentItem["ReportsTo"].Text)
            {
                //dragging the item to a child of itslef
            }
        }

Regards,
Marin
the Telerik team

[Max McKinney]

Thanks for the reply, I really appreciate it.  This solution would seem to work as long as the destination is a direct child of the dropped parent.  It seems to me this would not work if you dropped a parent onto a child whose parent was a child of the parent (i.e. nested relationship 2+ levels deep).  Surely there must be some solution that detects if the destination is a child no matter what depth within the tree.  Dropping a parent into a child would have obvious negative affects on the hierarchy so I must find a solution.

Thanks again for all the help.

[Marin]

Hello Max,

 Here is what the recursive version of the code will look like. It should work arbitrary level deep.

protected void RadGrid1_RowDrop(object sender, GridDragDropEventArgs e)
        {
            var sourceItemID = e.DraggedItems[0]["EmployeeID"].Text;

            var destinationItem = e.DestDataItem;

            if (IsChildOrDescendant(sourceItemID, destinationItem))
            {
                //dragging the item to a child of itslef
            }
        }

        private bool IsChildOrDescendant(string sourceItemID, GridDataItem destinationItem)
        {
            var parentItem = destinationItem.OwnerTableView.ParentItem;
            if (parentItem==null)
            {
                return false;
            }
            if (sourceItemID == parentItem["EmployeeID"].Text)
            {
                return true;
            }
            else
            {
                //recursive call
                return IsChildOrDescendant(sourceItemID, parentItem);
            }
        }

Best wishes,
Marin
the Telerik team

[Max McKinney]

thank you kindly.  this is exactly what I needed.

[Max McKinney]

In case someone else is interested, I made a few small changes that make the example more relevant to self referencing hierarchy:

protected void RadGrid1_RowDrop(object sender, GridDragDropEventArgs e)
        {
            var sourceItemID = e.DraggedItems[0].GetDataKeyValue("ContentID").ToString();

            var destinationItem = e.DestDataItem;

            if (IsChildOrDescendant(sourceItemID, destinationItem))
            {
                //dragging the item to a child of itslef
            }
        }

        private bool IsChildOrDescendant(string sourceItemID, GridDataItem destinationItem)
        {
            if (destinationItem==null)
            {
                return false;
            }
            if (sourceItemID == destinationItem.GetDataKeyValue("ParentContentID").ToString())
            {
                return true;
            }
            else
            {
                //recursive call
                return IsChildOrDescendant(sourceItemID, destinationItem.OwnerTableView.ParentItem);
            }
        }